Systems and methods for processing ammonia

ABSTRACT

The present disclosure provides systems and methods for processing ammonia. The system may comprise one or more reactor modules configured to generate hydrogen from a source material comprising ammonia. The hydrogen generated by the one or more reactor modules may be used to provide additional heating of the reactor modules (e.g., via combustion of the hydrogen), or may be provided to one or more fuel cells for the generation of electrical energy.

CROSS-REFERENCE

This application is a continuation of International Pat. Application No.PCT/US2022/029264 filed May 13, 2022, which claims the benefit of U.S.Provisional Application No. 63/188,593, filed May 14, 2021, U.S.Provisional Application No. 63/215,843, filed Jun. 28, 2021, U.S.Provisional Application No. 63/236,048, filed Aug. 23, 2021, U.S.Provisional Application No. 63/247,054, filed Sep. 22, 2021, U.S.Provisional Application No. 63/292,122, filed Dec. 21, 2021, U.S.Application No. 17/366,633, filed Jul. 2, 2021, and U.S. Application No.17/401,993, filed Aug. 13, 2021, each of which is incorporated herein byreference in its entirety for all purposes.

BACKGROUND

Various systems may be operated using a fuel source. The fuel source mayhave a specific energy corresponding to an amount of energy stored orextractable per unit mass of fuel. The fuel source may be provided tothe various systems to enable such systems to generate energy and/ordeliver power (e.g., for movement or transportation purposes).

SUMMARY

Hydrogen can be leveraged as a clean energy source to power varioussystems. Hydrogen can provide a distinct advantage over other types offuel such as diesel, gasoline, or jet fuel, which have specific energiesof about 45 megajoules per kilogram (MJ/kg) (heat), or lithium-ionbatteries, which have a specific energy of about 0.95 MJ/kg(electrical). In contrast, hydrogen has a specific energy of over 140MJ/kg (heat). As such, 1 kg of hydrogen can provide the same amount ofenergy as about 3 kg of gasoline or kerosene. Thus, hydrogen as a fuelsource can help to reduce the amount of fuel (by mass) needed to providea comparable amount of energy as other traditional sources of fuel.Further, systems that use hydrogen as a fuel source (e.g., as acombustion reactant) generally produce benign or nontoxic byproductssuch as water while producing minimal or near zero greenhouse gas (e.g.,carbon dioxide and nitrous oxide) emissions, thereby reducing theenvironmental impacts of various systems (e.g., modes of transportation)that use hydrogen as a fuel source.

Recognized herein are various limitations with hydrogen storage andproduction systems currently available. Although hydrogen has arelatively high gravimetric density (measured in MJ/kg), fuel storagesystems for compressed and liquefied hydrogen are often complex due tothe need to provide and maintain specialized storage conditions. Forexample, storage of hydrogen as a gas may require high-pressure tanks(e.g., 350-700 bar or 5,000-10,000 psi). Storage of hydrogen as a liquidmay require cryogenic temperatures because the boiling point of hydrogenat a pressure of 1 atm is -252.8° C. Further recognized herein arevarious limitations with commercially available ammonia processingsystems, which generally have slow startup times, non-ideal thermalcharacteristics, suboptimal ammonia conversion efficiencies, and highweight and volume requirements.

The present disclosure provides systems and methods to address at leastthe abovementioned shortcomings of conventional systems for processingammonia and producing, storing, and/or releasing hydrogen forutilization as a fuel source (e.g., at a fueling station or a powergeneration system). The embodiments of the present disclosure relategenerally to systems and methods for processing a source material toproduce or extract a fuel source. The fuel source may comprise hydrogen.The source material may comprise any material or compound comprisinghydrogen (e.g., a hydrocarbon). In some cases, the source material maycomprise ammonia (NH3).

The present systems and methods are advantageous in several ways. Someembodiments of the present systems and methods enable thedecarbonization of long-distance transportation (e.g., using ammonia asa source material and hydrogen as a fuel source) where refueling can bedifficult via other decarbonized methods (for example, on truckingroutes longer than 500 miles, or on transoceanic shipping routes). Oversuch long-distance routes, using batteries to power motors may entailexcessively long recharging times and excessive weight and volumerequirements, which reduces revenues for ship operators by decreasingthe space available for cargo. Additionally, using only hydrogen (e.g.,that is stored as pure hydrogen and not converted from ammonia) oversuch long-distance routes may be unviable due to the specialized storageconditions for hydrogen, described previously, as well as the largevolume requirements for the storage tanks. Thus, some embodiments of thepresent systems and methods, when utilizing ammonia as a source materialand hydrogen as a fuel source, may generate high electrical power (5kilowatts or greater) while comprising a high energy density (655 Wh/kgor greater by weight and 447 Wh/L or greater by volume).

Additionally, some embodiments of reactors in the present disclosure maybe heated by the combustion of hydrogen extracted from ammonia (asopposed to heating the reactors by combusting hydrocarbons or ammonia,which may undesirably emit greenhouse gases, nitrogen oxides (NO_(x)),and/or particulate matter). In some embodiments, by decomposing orcracking ammonia into hydrogen, a separate tank may not be required forstoring combustion fuel (e.g., hydrocarbons, hydrogen, or ammonia) forheating the reactor modules of the present disclosure.

Additionally, some embodiments of the present systems and methods mayprovide a stream of hydrogen that is highly purified of trace ammonia(e.g., 99% purity or higher), or a stream of hydrogen mixed withnitrogen including trace ammonia (e.g., below 1 ppm), by leveraging highammonia conversion efficiency (achieved by reactor and catalyst designsof the present disclosure) with adsorbents to remove unconvertedammonia. In some embodiments, the highly pure stream of hydrogen (orhydrogen mixed with nitrogen) may be consumed by a proton exchangemembrane fuel cell (PEMFC) or other power generation device (e.g.,internal combustion engine [ICE] or solid oxide fuel cell [SOFC]).

Additionally, the present systems and methods may be simple to operateand provide a high degree of safety. In some embodiments, ammonia may beintroduced using a single inlet from an ammonia tank (e.g., as opposedto a first inlet for a first reactor module, a second inlet for a secondreactor module, and so on). In some embodiments, a single stream ofammonia passes all of the reactor modules (e.g., first passing a startupreactor, and then into a main reactor, or vice versa). In someembodiments, this configuration may transfer excess heat from thereactor modules to the ammonia input from the storage tank (facilitatingthe vaporization of liquid ammonia), and may ensure a sufficiently highammonia conversion efficiency. In some embodiments, the ammonia flowrate may be controlled at the single inlet, and in the case of a majorfault or dangerous event, the ammonia flow may be quickly shut off viathe single inlet.

In one aspect, the present disclosure provides a system for processingammonia. The system may comprise a first reactor module configured toreceive a source material comprising ammonia, wherein the first reactormodule comprises (i) a first catalyst and (ii) a startup heating andreforming unit, wherein the startup heating and reforming unit comprisesone or more electrodes for passing a current through the first catalystto heat the first catalyst, wherein the first catalyst is configured toproduce or extract hydrogen from the ammonia when the first catalyst isheated using the startup heating and reforming unit; and a secondreactor module in fluid communication with the first reactor module,wherein the second reactor module is configured to receive the sourcematerial comprising the ammonia, wherein the second reactor modulecomprises (i) a second catalyst and (ii) one or more main heating unitsfor heating the second catalyst, wherein at least one of the one or moremain heating units is configured to heat at least a portion of thesecond catalyst by combusting the hydrogen generated by the firstreactor module, wherein the second catalyst is configured to produce orextract hydrogen from the ammonia when the second catalyst is heatedusing the one or more main heating units.

In some embodiments, the one or more ammonia fuel sources comprise oneor more liquid fuel storage tanks, wherein the ammonia is stored asliquid ammonia in the one or more liquid fuel storage tanks.

In some embodiments, the liquid ammonia is stored at a temperatureranging from about 15 to about 30° C. and at an absolute pressureranging from 7 to 12 bar. In some embodiments, the liquid ammonia isstored at a gauge pressure ranging from about atmospheric pressure toabout 20 bar. In some embodiments, the liquid ammonia is stored at atemperature ranging from about -40 to about 20° C. and at an absolutepressure ranging from about 0.5 bar to about 9 bar.

In some embodiments, the one or more main heating units comprise anelectrical heater or a combustion heater. In some embodiments, the oneor more electrodes comprise one or more metal electrodes. In someembodiments, the one or more metal electrodes may comprise copper.

In some embodiments, at least one of the first catalyst and the secondcatalyst comprises a metal foam catalyst. In some embodiments, the metalfoam catalyst comprises nickel, iron, chromium, cobalt, molybdenum,copper, or aluminum. In some embodiments, the metal foam catalystcomprises one or more alloys comprising nickel, iron, chromium, cobalt,molybdenum, copper, or aluminum. In some embodiments, the metal foamcatalyst comprises a catalytic coating of one or more powder or pelletcatalysts. In some embodiments, the catalytic coating comprises a metalmaterial, a promoter material, a support material, or any combinationthereof. In some embodiments, the metal material comprises ruthenium,nickel, rhodium, iridium, cobalt, iron, platinum, chromium, palladium,or copper. In some embodiments, the promoter material comprises at leastone material selected from Li, Na, K, Rb, Cs, Mg, Ca, Ba, Sr, La, Ce,Pr, Sm, or Gd. In some embodiments, the support comprises at least onematerial selected from Al₂O₃, MgO, CeO₂, ZrO₂, La₂O₃, SiO₂, Y₂O₃, TiO₂,SiC, hexagonal BN (boron nitride), BN nanotubes, silicon carbide, one ormore zeolites, LaAlO₃, CeAlO₃, MgAl₂O₄, CaAl₂O₄, or one or more carbonnanotubes.

In some embodiments, the catalytic coating comprises one or moreruthenium-based precursors. In some embodiments, the one or moreruthenium-based precursors comprise RuCl₃ or Ru₃(CO)₁₂. In someembodiments, the metal foam catalyst has an apparent electricalresistivity of at least about 8 micro ohm-meters (µΩm). In someembodiments, the metal foam catalyst is processed using one or moreetching, leaching, or acidic treatments to enhance a surface area of themetal foam catalyst. In some embodiments, the metal foam catalyst isheat treated and thermally activated. In some embodiments, the metalfoam catalyst is coated using a physical vapor deposition or chemicalvapor deposition treatment.

In some embodiments, the first reactor module comprises a plurality ofmodular units that are stackable on top of each other. In someembodiments, each of the plurality of modular units comprises a metalfoam catalyst and one or more reactor channels for directing ammonia tothe metal foam catalyst. In some embodiments, the system may furthercomprise one or more insulated panels for separating the plurality ofmodular units, wherein the one or more insulated panels compriseelectrical insulation coatings, wherein the electrical insulationcoatings are positioned between the plurality of modular units.

In some embodiments, the hydrogen generated using the first reactormodule is usable to power one or more fuel cells or to heat the secondreactor module via combustion. In some embodiments, the first reactormodule provides a startup time of at most about 5 minutes to reach atarget temperature of at least about 550° C. In some embodiments, thefirst reactor module provides a startup time of at most about 60 minutesto reach a target temperature of at least about 550° C. In someembodiments, the first reactor module provides an ammonia conversionefficiency of at least about 90%. In some embodiments, the first reactormodule has a power density of about 10 watts of electrical power percubic centimeter of reactor bed volume. In some embodiments, the systemhas a system level electrical energy density of at least about 600watt-hours per kilogram. In some embodiments, the system has a hydrogenstorage capacity of at least about 5% by weight. In some embodiments, atleast one of the first reactor module and the second reactor module isconfigured for self-heat generation from electricity or hydrogencombustion.

In some embodiments, the system may further comprise one or more fuelcells in fluid communication with at least one of the first reactormodule and the second reactor module. In some embodiments, the systemmay further comprise a hybrid battery for load following and initialreactor heating power. In some embodiments, the hybrid battery is inelectrical communication with at least one of the first reactor moduleand the second reactor module.

In some embodiments, the second reactor module is in fluid communicationwith the first reactor module to permit a transport of hydrogen,nitrogen, or ammonia between the first reactor module and the secondreactor module. In some embodiments, the second reactor module is inthermal and/or fluid communications with the first reactor module. Insome embodiments, the source material is provided to the first reactormodule and the second reactor module from a same source. In someembodiments, the source material is provided to the first reactor moduleand the second reactor module from different sources.

In some embodiments, the system may further comprise one or more springsadjacent to the catalyst and/or the one or more electrodes, wherein theone or more springs are configured to lighten or redistribute mechanicalloads on the catalyst when the catalyst undergoes one or more thermalcycling procedures. In some embodiments, the one or more springscomprise one or more metal springs. In some embodiments, the one or moresprings comprise one or more copper springs. In some embodiments, theone or more springs are configured to alleviate thermal stresses on thecatalyst due to a thermal expansion or a thermal contraction of thecatalyst during one or more thermal cycling procedures.

In another aspect, the present disclosure provides a method forprocessing ammonia, comprising: (a) providing (i) a first reactor modulecomprising a first catalyst and a startup heating and reforming unit and(ii) a second reactor module in fluid communication with the firstreactor module, wherein the second reactor module comprises a secondcatalyst and one or more main heating units; (b) using the startupheating and reforming unit to pass a current through the first catalystto heat the first catalyst, wherein the first catalyst is configured toproduce or extract hydrogen from ammonia when heated; and (c) using atleast one of the one or more main heating units to heat at least aportion of the second catalyst by combusting the hydrogen generatedusing the first reactor module and/or the second reactor module.

In some embodiments, the method may further comprise using the secondcatalyst to produce or extract hydrogen from ammonia, wherein the secondcatalyst is configured to produce or extract the hydrogen from theammonia when heated. In some embodiments, the method may furthercomprise directing at least a portion of the hydrogen generated usingthe second catalyst to one or more fuel cells to generate electricalenergy. In some embodiments, the method may further comprise directingat least a portion of the hydrogen generated using the first catalyst toone or more fuel cells to generate electrical energy.

In another aspect, the present disclosure provides a system comprising:a reactor module configured to receive a source material comprisingammonia, wherein the reactor module comprises a catalyst and a pluralityof heating units for heating the catalyst, wherein the plurality ofheating units comprises a first heating unit configured to heat at leasta first portion of the catalyst by combustion and a second heating unitconfigured to heat at least a second portion of the catalyst usingelectrical heating, wherein the catalyst is configured to produce orextract hydrogen from the ammonia when the catalyst is heated using theplurality of heating units.

In some embodiments, the second heating unit is configured to heat thesecond portion of the catalyst by passing an electrical current throughthe second portion of the catalyst. In some embodiments, the system mayfurther comprise a secondary reactor module in fluid and/or thermalcommunication with the reactor module, wherein the secondary reactormodule comprises a secondary catalyst and a secondary heating unit,wherein the secondary heating unit is configured to heat the secondarycatalyst, wherein the secondary catalyst is configured to produce orextract hydrogen from the ammonia when the secondary catalyst is heatedusing the secondary heating unit.

In some embodiments, the first heating unit of the reactor module isconfigured to heat the first portion of the catalyst by combustinghydrogen gas generated using the secondary reactor module. In someembodiments, the first heating unit is configured to heat the firstportion of the catalyst by combusting leftover hydrogen gas from one ormore fuel cells in fluid communication with the reactor module or thesecondary reactor module. In some embodiments, the secondary heatingunit comprises one or more electrodes for passing a current through thesecondary catalyst to heat the secondary catalyst.

In some embodiments, a heat load distribution between the first heatingunit and the second heating unit is adjustable to increase an ammoniacracking conversion efficiency and to enhance a thermal reformingefficiency of the reactor module. In some embodiments, the system mayfurther comprise a controller configured to control an operation of thefirst heating unit and the second heating unit to adjust the heat loaddistribution within the reactor module. In some embodiments, the heatload distribution comprises a heating power ratio corresponding to aratio between a heating power of the first heating unit and a heatingpower of the second heating unit.

In some embodiments, the reactor module has a thermal reformingefficiency of at least about 80%. In some embodiments, the reactormodule has a thermal reforming efficiency of at least about 90%. In someembodiments, the reactor module has a thermal reforming efficiency of atleast about 95%. In some embodiments, the reactor module comprises acartridge heater design that utilizes one or more electrical insulationmaterials with a high heat transfer coefficient. In some embodiments,the one or more electrical insulation materials comprise boron nitride.In some embodiments, the reactor module comprises a reaction bedcomprising one or more ammonia decomposition catalysts comprising ametal material, a promoter material, and a support material. In someembodiments, the first heating unit and the second heating unit areconfigured to heat different portions of the reaction bed. In someembodiments, the metal material comprises ruthenium, nickel, rhodium,iridium, cobalt, iron, platinum, chromium, palladium, or copper. In someembodiments, the promoter material comprises at least one materialselected from Li, Na, K, Rb, Cs, Mg, Ca, Ba, Sr, La, Ce, Pr, Sm, or Gd.In some embodiments, the support comprises at least one materialselected from Al₂O₃, MgO, CeO₂, ZrO₂, La₂O₃, SiO₂, Y₂O₃, TiO₂, SiC,hexagonal BN (boron nitride), BN nanotubes, silicon carbide, one or morezeolites, LaAlO₃, CeAlO₃, MgAl₂O₄, CaAl₂O₄, or one or more carbonnanotubes.

In some embodiments, the reactor module comprises one or more wallshaving a thickness that ranges from about 0.5 millimeters to about 1.5millimeters to reduce thermal mass and to provide a faster and moredynamic temperature response. In some embodiments, the reactor modulecomprises one or more walls having a thickness that ranges from about1.5 millimeters to about 10 millimeters (to increase structuralintegrity). In some embodiments, the system may further comprise one ormore fuel cells in fluid communication with the reactor module, whereinthe one or more fuel cells are configured to generate electrical energyusing the hydrogen generated by the reactor module.

In some embodiments, the plurality of heating units comprises at leasttwo or more heating units. In some embodiments, a heat load distributionbetween the at least two or more heating units is adjustable to increasean ammonia conversion efficiency and to enhance a thermal reformingefficiency of the reactor module. In some embodiments, each of the atleast two or more heating units have one or more heating zones in thereactor module to allow for a continuous heat distribution within one ormore regions in the reactor module. In some embodiments, the at leasttwo or more heating units are configured to heat different zones in thereactor module. In some embodiments, the at least two or more heatingunits are configured to heat one or more same zones in the reactormodule. In some embodiments, the first portion and the second portionare different portions of the catalyst. In some embodiments, theelectrical heating comprises Joule heating.

In another aspect, the present disclosure provides a method, comprising:(a) providing a reactor module comprising a catalyst and a plurality ofheating units for heating the catalyst, wherein the plurality of heatingunits comprises a first heating unit and a second heating unit, whereinthe catalyst is configured to produce or extract hydrogen from ammoniawhen the catalyst is heated using the plurality of heating units; and(b) using (i) the first heating unit to heat at least a first portion ofthe catalyst by combustion and (ii) the second heating unit to heat atleast a second portion of the catalyst by electrical heating.

In some embodiments, the method may further comprise using the catalystto extract hydrogen from ammonia. In some embodiments, the method mayfurther comprise directing the extracted hydrogen to one or more fuelcells to generate electrical energy. In some embodiments, using thefirst heating unit to heat at least the first portion of the catalystcomprises combusting hydrogen gas generated using a secondary reactormodule. In some embodiments, using the second heating unit to heat atleast the second portion of the catalyst comprises passing an electricalcurrent through the second portion of the catalyst. In some embodiments,the method may further comprise adjusting a heat load distributionbetween the first heating unit and the second heating unit to increasean ammonia conversion efficiency and to enhance a thermal reformingefficiency of the reactor module.

In another aspect, the present disclosure provides a system forprocessing ammonia, comprising: one or more reactors for decomposingammonia using one or more catalysts; one or more heat exchangers forheating at least an inlet flow or for cooling at least an exit flow ofthe one or more reactors; and one or more adsorption towers forfiltering or removing one or more trace materials from the exit flow ofthe one or more reactors. In some embodiments, the one or moreadsorption towers comprise one or more adsorbents having a cartridgeform factor. In some embodiments, the one or more reactors comprise astartup reactor and a main reactor. The startup reactor may beconfigured to decompose ammonia into hydrogen and provide at least saidhydrogen to the main reactor as a fuel for combustion heating. In someembodiments, the startup reactor is configured to heat the one or morecatalysts using electrical heating, resistive heating, inductiveheating, or Joule heating. In some embodiments, the startup reactor isin fluid communication and/or thermal communication with the mainreactor. In some embodiments, the one or more adsorption towers comprisetwo or more adsorbent beds for on-demand adsorbent regeneration andcontinuous system operation.

In some embodiments, the system may further comprise one or more valvesor flow control units for selectively diverting the reactor exit flowbetween a first adsorbent bed and a second adsorbent bed. In someembodiments, the system may further comprise a controller configured tocontrol the one or more valves or flow control units to divert thereactor exit flow to a regenerated adsorbent bed. In some embodiments,the system may further comprise one or more additional heat exchangersfor regenerating the one or more adsorbent towers. In some embodiments,the system may further comprise a pump or a blower configured to removetrace ammonia from the reactor exit flow and to combine a stream of thetrace ammonia with an exit flow from a fuel cell in fluid communicationwith a combustion heater of the one or more reactors and/or the one ormore adsorbent towers (e.g., during adsorbent regeneration). In someembodiments, the system may further comprise one or more fuel cells influid communication with the one or more reactors. In some embodiments,the system may further comprise one or more ammonia tanks in fluidcommunication with the one or more reactors. In some embodiments, theone or more heat exchangers for the exit flows and/or inlet flows of thereactors may be in thermal communications with an ammonia storage tankto provide heating energy for ammonia evaporation inside the ammoniastorage tank. In some embodiments, the exit flows and/or inlet flows ofthe reactors may be in thermal communications with the flow from theammonia storage tank for ammonia evaporation and/or to increase thetemperature. In some embodiments, the system may further comprise anammonia storage tank in thermal communication with one or more fuelcells to recover waste heat from the one or more fuel cells to provideheating energy for the ammonia evaporation in the ammonia storage tank.In some embodiments, the system may comprise one or more heat exchangersin thermal communication with one or more fuel cells to recover wasteheat from the one or more fuel cells to provide heating energy for theammonia evaporation inside the one or more heat exchangers. In someembodiments, the reactor inlet flow or the exit flow comprises at leastone of hydrogen, nitrogen, and ammonia. In some embodiments, the one ormore trace materials comprise ammonia. In some embodiments, the ammoniacomprises unconverted ammonia. In some embodiments, the system mayfurther comprise one or more additional heat exchangers in thermalcommunication with an ammonia storage tank to provide heating energy forammonia evaporation inside the ammonia storage tank.

In some embodiments, the one or more reactors may be configured to bemounted to a vehicle. In some embodiments, the vehicle comprises aterrestrial vehicle, an aerial vehicle, or an aquatic vehicle (e.g., aboat, a ship, or any other type of maritime vehicle). In someembodiments, the one or more reactors are configured to be mounted in afront region, a back region, a side region, an inner region, an outerregion, an upper region, or a lower region of the vehicle. In someembodiments, the one or more reactors, the one or more heat exchangers,and the one or more adsorption towers are configured to be mounted indifferent portions or regions of a vehicle. In some embodiments, thevehicle comprises a drone, an automobile, or a truck. In someembodiments, the vehicle is configured to be operated by a human or acomputer. In some embodiments, the vehicle is autonomous orsemi-autonomous.

In another aspect, the present disclosure provides a system comprising:(a) an ammonia storage tank; (b) a reactor in fluid communication withthe ammonia storage tank, wherein the reactor is configured to decomposeammonia received from the ammonia storage tank to generate a reactorexit flow comprising hydrogen; (c) one or more adsorbents configured tofilter out or remove unconverted ammonia from at least a portion of thereactor exit flow to provide a filtered reactor exit flow; (d) one ormore fuel cells in fluid communication with at least one of the reactorand the one or more adsorbents, wherein the one or more fuel cells areconfigured to (i) receive the filtered reactor exit flow from the one ormore adsorbents (ii) process the filtered reactor exit flow to generateelectricity, and (iii) output a fuel cell exit flow comprisingunconverted hydrogen; and (e) one or more combustors embedded at leastpartially within the reactor, wherein the one or more combustors are (i)in fluid communication with at least one of the ammonia storage tank,the reactor, the one or more adsorbents, and the one or more fuel cells,and (ii) configured to combust at least a portion of ammonia flow fromthe ammonia tank, the reactor exit flow, the filtered reactor exit flow,or the fuel cell exit flow to generate thermal energy for heating thereactor in a plurality of different regions to facilitate ammoniadecomposition.

In some embodiments, the one or more combustors are configured tocombust at least a portion of the reactor exit flow to heat theplurality of different regions within the reactor. In some embodiments,the reactor exit flow further comprises undecomposed ammonia. In someembodiments, the reactor exit flow further comprises nitrogen.

In some embodiments, the one or more combustors are configured tocombust at least a portion of the fuel cell exit flow to heat theplurality of different regions within the reactor. In some embodiments,the fuel cell exit flow further comprises hydrogen. In some embodiments,the fuel cell exit flow further comprises nitrogen.

In some embodiments, the one or more combustors comprise one or moredistinct combustion zones configured to heat the plurality of differentregions within the reactor. In some embodiments, the one or morecombustors comprise one or more air-fuel contact zones configured to mixa flow comprising hydrogen and a flow comprising oxygen to facilitatecombustion.

In some embodiments, the one or more combustors comprise a cylindricalshape or a circular cross-section. In some embodiments, the one or morecombustors are concentric to the reactor.

In some embodiments, the system further comprises an air supply unit influid communication with the one or more combustors, wherein the airsupply unit is configured to supply at least oxygen to the one or morecombustors. In some embodiments, the air supply unit comprises a fan, ablower, a compressor, a compressed cylinder, a venturi restriction, aturbine, or a turbocharging unit. In some embodiments, the air supplyunit comprises a turbocharging unit driven by a combustor exit flow fromthe one or more combustors.

In some embodiments, the system comprises a mobile system with a volumeof at most about 2 m³.

In some embodiments, the one or more combustors comprise a rectangularshape or a rectangular cross-section.

In some embodiments, the one or more combustors comprise a hightemperature refractory material configured to enhance combustorstability. In some embodiments, the high temperature refractory materialcomprises alumina, magnesia, silica, lime, steel, tungsten, molybdenum,tungsten carbide, or any combination thereof. In some embodiments, thehigh temperature refractory material comprises a metal oxide selectedfrom the group consisting of: Al₂O3, SiO₂, ZrO₂, VO₂, Ta, Ni alloy, Alalloy, Mo alloy, Cr alloy, Si alloy, or any combination thereof. In someembodiments, the refractory material is coated on one or more surfacesof the one or more combustors.

In some embodiments, the filtered reactor exit flow comprises at mostabout 100 ppm ammonia. In some embodiments, the filtered reactor exitflow comprises at most about 10 ppm ammonia.

In some embodiments, the one or more combustors comprise an atmosphericcombustor, a naturally aspirated combustor, a swirl combustor, or apressurized combustor. In some embodiments, the atmospheric combustor isconfigured to receive a supply of air or oxygen from a compressedcylinder or an air supply unit (e.g., fan, blower, compressor, etc.). Insome embodiments, the naturally aspirated combustor is configured toreceive a supply of air or oxygen from an ambient environment in partbased on a vacuum induced within the combustor. In some embodiments, thepressurized combustor is configured to receive a supply of air or oxygenfrom an air supply unit (e.g., fan, blower, compressor, etc.). coupledto a turbine, wherein the turbine is driven by one or more exhaust gasesfrom the pressurized combustor.

In some embodiments, the one or more combustors are configured tocombust a mixture of air and fuel that is at least partially pre-mixedupstream of a combustion region. In some embodiments, the one or morecombustors are configured to combust a mixture of air and fuel, whereinthe air and the fuel are mixed at or near the combustion region toproduce a flame. In some embodiments, the one or more combustors areconfigured to combust a mixture of air and fuel, wherein the air and thefuel are mixed at a set of premixing zones upstream of a combustionregion to enhance heat distribution. In some embodiments, each premixingzone in the set of premixing zones is configured to pre-combust at leasta portion of the mixture of air and fuel, thereby distributing heat moreuniformly throughout the combustor and reducing one or more local hotspot temperatures. In some embodiments, the set of premixing zonescomprises at least 1 premixing zone. In some embodiments, the set ofpremixing zones comprises at least 2 premixing zones. In someembodiments, the set of premixing zones comprises at least 3 premixingzones.

In some embodiments, the combustion fuel comprises at least one of thereactor exit flow, flow from the ammonia storage tank, the filteredreactor exit flow, or the fuel cell exit flow.

In some embodiments, the one or more combustors are configured tocombust at least a portion of the ammonia flow from the ammonia storagetank to generate thermal energy for heating the reactor in a pluralityof different regions to facilitate ammonia decomposition.

In another aspect, the present disclosure provides a system comprising:one or more reactors configured to crack ammonia provided to the one ormore reactors to yield hydrogen, nitrogen, and/or ammonia; and one ormore fuel cells in fluid communication with the one or more reactors,wherein the one or more fuel cells are configured to receive and processthe hydrogen to generate electrical energy, wherein the one or morereactors and the one or more fuel cells are configured to be mounted onor to an aerial vehicle, wherein the one or more fuel cells are inelectrical communication with one or more motors or drive units of theaerial vehicle to drive the one or more motors or drive units of theaerial vehicle.

In some embodiments, the one or more reactors comprise a startup reactorand a main reactor.

In some embodiments, the startup reactor is configured to crack at leasta portion of the ammonia provided to the one or more reactors to yieldhydrogen, nitrogen, and/or ammonia. In some embodiments, the startupreactor is in fluid communication with the main reactor, wherein themain reactor is configured to combust at least a portion of an exit flowfrom the startup reactor to heat the main reactor.

In some embodiments, the exit flow from the startup reactor compriseshydrogen and at least one of ammonia or nitrogen.

In some embodiments, the one or more reactors comprise two or morestartup reactors and two or more main reactors.

In some embodiments, the system further comprises a controllerconfigured to control a flow of the ammonia provided to the one or morereactors based on a desired power output from the one or more fuelcells.

In some embodiments, the system further comprises one or more adsorbentsin fluid communication with the one or more reactors, wherein the one ormore adsorbents are configured to process an exit flow from the one ormore reactors to filter out or remove ammonia from the exit flow,wherein the exit flow comprises at least hydrogen and/or nitrogen.

In some embodiments, the adsorbents are in fluid communication with theone or more fuel cells, wherein the adsorbents are configured to directthe hydrogen and/or the nitrogen to the one or more fuel cells afterfiltering out or removing the ammonia from the exit flow of the one ormore reactors.

In some embodiments, the system further comprises one or more combustorsin fluid communication with the one or more fuel cells, wherein the oneor more combustors are configured to combust an exit flow from the oneor more fuel cells to heat the one or more reactors.

In some embodiments, the exit flow from the one or more fuel cellscomprises unconverted hydrogen.

In some embodiments, the one or more fuel cells are in communicationwith an electrical load.

In some embodiments, the electrical load comprises the one or moremotors or drive units of the aerial vehicle.

In some embodiments, the one or more combustors are positioned at leastpartially within the one or more reactors.

In some embodiments, the system further comprises an auxiliary batteryfor powering the one or more motors or drive units of the aerialvehicle.

In some embodiments, the system further comprises one or more heatexchangers for cooling an exit flow of the one or more reactors. In someembodiments, the system further comprises one or more heat exchangersfor vaporizing and/or heating a flow from the one or more fuel storagetanks.

In some embodiments, the system further comprises one or more fuelstorage tanks mounted on the aerial vehicle, wherein the fuel storagetanks are in fluid communication with the one or more heat exchangersand/or the one or more reactors to provide the ammonia.

In some embodiments, the one or more fuel cells are in thermalcommunication with the one or more fuel storage tanks and/or one or moreheat exchangers to facilitate a transfer of thermal energy from the oneor more fuel cells to the one or more fuel storage tanks and/or one ormore heat exchangers to heat the one or more fuel storage tanks and/orone or more heat exchangers for ammonia evaporation.

In some embodiments, the one or more heat exchangers are in thermalcommunication with an exit flow from the one or more fuel cells to coolthe heat exchangers and/or the exit flow from the one or more reactors,wherein the exit flow from the one or more fuel cells comprises at leastair or oxygen.

In some embodiments, the system further comprises a controlleroperatively coupled to one or more valves for controlling (i) a flow ofthe ammonia to the one or more reactors or the one or more heatexchangers or (ii) a flow of hydrogen to the one or more fuel cells. Insome embodiments, the controller is configured to provide dynamic powercontrol by controlling an operation of the one or more valves.

In some embodiments, each of the one or more reactors is configured tocrack at least about 30 liters of ammonia per minute.

In some embodiments, the system further comprises a controller and oneor more sensors operatively coupled to the controller, wherein thecontroller is configured to monitor a temperature of the one or morereactors, a flow pressure of the ammonia and/or hydrogen, and/or anelectrical output of the one or more fuel cells based on one or moremeasurements obtained using the one or more sensors. In someembodiments, the controller is configured to increase a power of an airsupply unit to increase an air flow rate to one or more combustors ofthe one or more reactors when a temperature of the one or more reactorsdecreases or falls below a threshold temperature. In some embodiments,the controller is configured to modulate one or more valves connected toan ammonia storage tank to maintain or reach a threshold pressure pointcorresponding to a desired ammonia flow rate and power output.

In some aspects, the present disclosure provides a system for processingammonia, comprising: one or more reactors for decomposing ammonia; oneor more heating elements embedded in at least one of the one or morereactors; and one or more flow channels provided around or adjacent tothe one or more heating elements to enhance flow field and heatinguniformity, wherein the one or more heating elements are configured toheat a fluid comprising one or more reforming gases as the fluid flowsalong the one or more flow channels provided around or adjacent to theone or more heating elements.

In some embodiments, each of the one or more reactors is configured tooutput a volume or amount of hydrogen that is usable to generate atleast about 25 kilowatts of power.

In some embodiments, the one or more reactors comprise one or moreenclosed or partially enclosed regions which (i) comprise the one ormore flow channels and (ii) surround the one or more heating elements,wherein the one or more enclosed or partially enclosed regions allow apassage of the one or more reforming gases around the one or moreheating elements to facilitate heat transfer between the one or moreheating elements and the one or more reforming gases.

In some embodiments, the one or more heating elements comprise acombustion heater, an electrical heater, or a hybrid heating unitcomprising both the combustion heater and the electrical heater.

In some embodiments, the hybrid heating unit comprises the combustionheater and the electrical heater in series along a length of the atleast one reactor.

In some embodiments, the hybrid heating unit comprises the combustionheater and the electrical heater in parallel orthogonal to a length ofthe at least one reactor.

In some embodiments, the system further comprises one or more catalystsconfigured to decompose or crack ammonia when heated by the one or moreheating elements.

In some embodiments, the one or more catalysts are provided outside ofor external to the one or more heating elements.

In some embodiments, the one or more heating elements comprise one ormore external surfaces in thermal communication with the fluid flowingalong or through the one or more flow channels, wherein the one or morecatalysts are provided adjacent to and/or in thermal communication withthe external surfaces of the one or more heating elements.

In some embodiments, the one or more catalysts are located or providedwithin the one or more flow channels.

In some embodiments, the one or more flow channels comprise a circularcross-section to enable uniform heating of the fluid.

In some embodiments, the one or more gas inlets are configured todistribute flow of the fluid into a plurality of flow channels within atleast one reactor of the one or more reactors.

In some embodiments, the one or more heating elements are configured toprovide a plurality of heating zones within the reactors, wherein theplurality of heating zones have different temperatures and/or heatingpower that are predetermined or adjustable.

In some embodiments, the one or more reactors comprise a cross-sectionalshape comprising a circle, an ellipse, an oval, or any polygoncomprising three or more sides.

In some embodiments, the one or more flow channels comprise across-sectional shape comprising a circle, an ellipse, an oval, or anypolygon comprising three or more sides.

In some embodiments, the one or more reactors comprise a cross-sectionalshape that is similar to a cross-sectional shape of a flow channel inthe one or more flow channels.

In some embodiments, the one or more reactors comprise a cross-sectionalshape that is different than a cross-sectional shape of a flow channelin the one or more flow channels.

In some embodiments, the one or more reactors comprise (i) a first flowpath for passage of reforming gases from one or more gas inlets along aportion of the one or more heating elements and (ii) a second flow pathfor directing reformate gases to one or more gas outlets.

In some embodiments, the first flow path and the second flow path areoriented in different directions.

In some embodiments, the first flow path and the second flow path arepositioned adjacent to each other to enable a transfer of thermal energybetween (i) the one or more reforming gases entering the one or morereactors via the one or more gas inlets and (ii) one or more reformategases exiting the one or more reactors via the gas outlets.

In some embodiments, the system further comprises a plurality flowchannels, wherein a first flow channel of the plurality of flow channelsassociated with the first flow path, a second flow channel of the one ormore flow channels associated with the second flow path, or both thefirst flow channel and the second flow channel have one or more internalextended surfaces configured to enhance heat transfer.

In some embodiments, each individual heating element of the one or moreheating elements comprises one or more dedicated flow channels.

In some embodiments, the one or more heating elements each comprisedifferent respective flow channels.

In some embodiments, the one or more heating elements are configured to(i) control temperatures and/or heating powers of different regions ofthe one or more heating elements or the one or more reactors or (ii)adjust a location of one or more heating zones within the one or morereactors to optimize ammonia thermal reforming efficiency and/orconversion efficiency. The fuel reforming or conversion capabilities ofthe reactors may be determined or computed based on measurements takendownstream of the one or more reactors.

In some embodiments, the system further comprises a plurality ofdifferent catalysts for decomposing ammonia, wherein the plurality ofdifferent catalysts are in thermal communication with at least one ofthe one or more heating elements.

In some embodiments, the plurality of different catalysts comprise afirst catalyst with a first set of ammonia reforming properties and asecond catalyst with a second set of ammonia reforming properties.

In some embodiments, the first catalyst and the second catalyst are inthermal communication with different heating elements, differentlocations or regions of a same heating element, or different heatingzones generated by the one or more heating elements.

In some embodiments, the one or more flow channels comprise one or morebaffles to induce turbulence, mixing, increase flow residence time,and/or enhance flow uniformity and heat transfer.

In some embodiments, the system further comprises a controllerconfigured to control a flow of ammonia into the one or more flowchannels by modulating one or more flow control units.

In some embodiments, the controller is configured to control the flow ofammonia based on a heating power input and/or temperatures to each ofthe one or more heating elements.

In some embodiments, the system further comprises a controllerconfigured to control an operation or a temperature of the one or moreheating elements.

In some embodiments, the system further comprises one or more heatexchanger(s) between one or more hot outlet flow(s) and one or more coldinlet flow(s) of the one or more reactors.

In some embodiments, each of the one or more reactors is configured toreform at least about 300 L/min of ammonia. In some embodiments, each ofthe one or more reactors is configured to reform at least about 300standard liters per minute (SLM) of ammonia.

In some embodiments, the system further comprises: one or more fuelcells in fluid communication with the one or more reactors, wherein theone or more fuel cells are configured to receive and process hydrogengenerated by the decomposition of ammonia to produce electrical energy,wherein the system has an energy density of at least about 600 Wh/kg, atleast about 400 Wh/L, or both.

In some embodiments, the system further comprises a plurality ofreactors, wherein a first reactor in the plurality of reactors comprisesan electrical heater, and wherein a second reactor in the plurality ofreactors comprises a combustion heater, and wherein the first reactorand the second reactor are in fluidic communication in series or inparallel.

In another aspect, the present disclosure provides a system comprising:one or more reactors in fluid communication with one or more ammoniasources, wherein the one or more reactors comprise one or morecatalysts; and a plurality of heating elements in thermal communicationwith the one or more catalysts, wherein the one or more reactors areconfigured to produce or generate hydrogen from ammonia provided by orreceived from the one or more ammonia sources using the one or morecatalysts and the plurality of heating elements, wherein the pluralityof heating elements comprise at least one electrical heater and at leastone combustion heater.

In some embodiments, the one or more reactors comprise a first reactorand a second reactor in fluid communication with the first reactor.

In some embodiments, the first reactor comprises (i) a first catalystand (ii) a startup heating unit configured to heat the first catalyst,wherein the first catalyst is configured to produce or extract thehydrogen from the ammonia.

In some embodiments, the startup heating unit comprises the at least oneelectrical heater.

In some embodiments, the at least one electrical heater comprises one ormore electrodes for passing a current through the first catalyst to heatthe first catalyst.

In some embodiments, the second reactor comprises (i) a second catalystand (ii) one or more main heating units configured to heat the secondcatalyst, wherein the second catalyst is configured to produce orextract the hydrogen from the ammonia.

In some embodiments, the one or more main heating units comprise the atleast one combustion heater.

In some embodiments, the at least one combustion heater is configured toheat at least a portion of the second catalyst by combusting thehydrogen generated by the first reactor.

In some embodiments, the system further comprises the one or moreammonia sources.

In some embodiments, the one or more ammonia sources comprise one ormore liquid fuel storage tanks, wherein the ammonia is stored as liquidammonia in the one or more liquid fuel storage tanks.

In some embodiments, the liquid ammonia is stored at a temperatureranging from about 15 to about 30° C. and at an absolute pressureranging from 7 to 12 bar.

In some embodiments, the liquid ammonia is stored at a gauge pressureranging from about atmospheric pressure to about 20 bar.

In some embodiments, the liquid ammonia is stored at a temperatureranging from about -40 to about 20° C. and at an absolute pressureranging from about 0.5 bar to about 9 bar.

In some embodiments, the system further comprises one or more fuel cellsin fluid communication with the one or more reactors.

In some embodiments, the system further comprises one or more adsorbentsin fluid communication with the one or more reactors and the one or morefuel cells, wherein the one or more adsorbents are configured to filterout or remove unconverted ammonia from an exit flow from the one or morereactors.

In some embodiments, the one or more adsorbents are configured toprovide a filtered reactor exit flow to the one or more fuel cells.

In some embodiments, the one or more fuel cells are configured to (i)receive the filtered reactor exit flow from the one or more adsorbents,(ii) process the filtered reactor exit flow to generate electricity, and(iii) output a fuel cell exit flow comprising unconverted hydrogen.

In some embodiments, one or more heating elements of the plurality ofheating elements are in fluid and/or thermal communication with the fuelcell exit flow.

In some embodiments, the one or more heating elements are configured tocombust the unconverted hydrogen in order to heat the one or morecatalysts.

In some embodiments, the one or more reactors comprise one or more flowchannels for the ammonia, wherein the one or more flow channels (i)surround at least one heating element of the plurality of heatingelements and (ii) permit a flow of the ammonia around the at least oneheating element to facilitate heat transfer between the heating elementand the ammonia.

In some embodiments, the one or more reactors comprise one or more flowchannels adjacent to the plurality of heating elements, wherein the flowchannels permit a flow of the ammonia adjacent to or along the one ormore heating elements to facilitate heat transfer between the one ormore heating elements and the ammonia.

In some embodiments, each of the one or more flow channels is concentricor coaxial with a respective one of the one or more heating elementswith respect to a longitudinal axis.

In some embodiments, the plurality of heating elements are in fluidcommunication and/or thermal communication with the ammonia flowingalong or through the one or more flow channels.

In some embodiments, the one or more flow channels are provided aroundor adjacent to the heating elements to enhance flow field and heatinguniformity.

In some embodiments, the heating elements are configured to heat theammonia as the ammonia flows along or through the one or more flowchannels provided around or adjacent to the heating elements.

In some embodiments, the at least one combustion heater is configured tocombust an exit flow from the one or more reactors to generate thermalenergy for heating the one or more reactors.

In some embodiments, the at least one combustion heater is configured tocombust an exit flow from one or more adsorbents in fluid communicationwith the one or more reactors to generate thermal energy for heating theone or more reactors.

In some embodiments, the at least one combustion heater is configured tocombust an exit flow from one or more fuel cells in fluid communicationwith the one or more reactors to generate thermal energy for heating theone or more reactors.

In some embodiments, the at least one combustion heater comprises aswirl combustor, a diffusion flame combustor, a micro-mixer combustor,or any combination thereof.

In some embodiments, an exhaust of the at least one combustion heater isusable to heat or preheat the ammonia.

In some embodiments, the at least one combustion heater is configured tocombust a mixture of air and a combustion fuel comprising hydrogen.

In some embodiments, the at least one combustion heater comprises one ormore zones for mixing or premixing the air and the combustion fuelupstream of a combustion region of the at least one combustion heater.

In some embodiments, each of the one or more zones is configured tocombust or pre-combust at least a portion of the mixture of air and thecombustion fuel to uniformly distribute heat throughout the combustionheater and reduce local hot spot temperatures.

In some embodiments, the plurality of heating elements comprise a hybridheating unit comprising the at least one electrical heater and the atleast one combustion heater.

In some embodiments, the first reactor comprises the at least oneelectrical heater, and the second reactor comprises the at least onecombustion heater.

In some embodiments, the first reactor and the second reactor are influid communication in series so that a first exit flow of the firstreactor enters the second reactor.

In some embodiments, the first reactor and the second reactor are influid communication in parallel so that a first exit flow of the firstreactor and a second exit flow of the second reactor combine to form acombined exit flow.

In some embodiments, the one or more catalysts are provided adjacent toand/or in thermal communication with one or more external surfaces ofthe heating elements.

In some embodiments, the one or more reactors comprise a cross-sectionalshape that is selected from the group consisting of a circle, anellipse, an oval, and any polygon comprising three or more sides.

In some embodiments, the one or more reactors comprise one or more flowchannels having a cross-sectional shape selected from the groupconsisting of a circle, an ellipse, an oval, and any polygon comprisingthree or more sides.

In some embodiments, each of the one or more reactors comprises across-sectional shape that is similar to a cross-sectional shape of aflow channel of each respective reactor of the one or more reactors.

In some embodiments, each of the one or more reactors comprise across-sectional shape that is different than a cross-sectional shape ofa flow channel of each respective reactor of the one or more reactors.

In some embodiments, the one or more reactors comprise (i) a first flowpath for a reforming gas comprising the ammonia and (ii) a second flowpath for a reformate gas generated from processing of the reforming gas.

In some embodiments, the first flow path permits a flow of the reforminggas along at least a portion of the plurality of heating elements.

In some embodiments, the second flow path permits a flow of thereformate gas to one or more outlets of the reactors.

In some embodiments, the first flow path and the second flow path areoriented in different directions.

In some embodiments, the first flow path and the second flow path are influid communication with each other to enable heat transfer between thereforming gas and the reformate gas.

In some embodiments, the system further comprises one or more heatexchangers.

In some embodiments, the one or more heat exchangers are configured toexchange heat between an exit flow of the one or more reactors and aflow of the ammonia from the one or more ammonia sources.

In some embodiments, the one or more heat exchangers are configured tofacilitate a transfer of thermal energy between (i) a flow of theammonia from the one or more ammonia sources and (ii) one or more fuelcells in fluid communication with the one or more reactors, in order toevaporate the ammonia.

In some embodiments, the system further comprises one or more controlunits to modulate an exit flow of the one or more reactors and/or atemperature of the plurality of heating elements.

In some embodiments, the one or more control units comprise a controllerand one or more sensors operatively coupled to the controller.

In some embodiments, the controller is configured to monitor and control(i) a temperature of the one or more reactors, (ii) a flow pressure ofthe ammonia and/or hydrogen, and/or (iii) an electrical output of one ormore fuel cells in fluid communication with the one or more reactors,based at least in part on one or more measurements obtained using theone or more sensors.

In some embodiments, the controller is configured to reduce or increasean air flow rate, reduce or increase a combustion fuel flow rate, orreduce or increase both the air flow rate and the combustion fuel flowrate to the at least one combustion heater based on a temperature of theone or more reactors.

In some embodiments, the controller is configured to increase the airflow rate using a fan, a blower, or a compressor.

In some embodiments, the controller is configured to increase thecombustion fuel flow rate by increasing ammonia flow rate or reducingfuel cell hydrogen consumption.

In some embodiments, the controller is configured to reduce or increasea power output of the one or more fuel cells based on a temperature ofthe one or more reactors.

In some embodiments, the controller is configured to increase a flowrate of the ammonia to the one or more reactors based on a temperatureof the one or more reactors or power output of one or more fuel cells.

In some embodiments, the controller is configured to increase the flowrate of the ammonia using a valve and/or a pump.

In some embodiments, the system is configured to reform the ammonia at arate of at least about 50 L/min STP of ammonia gas.

In some embodiments, the controller is configured to increase ordecrease electrical power supplied to the at least one electrical heaterbased on a temperature of the one or more reactors.

In some embodiments, the system comprises an energy density of at leastabout 600 Wh/kg, or at least about 400 Wh/L.

In some embodiments, the system comprises an operating pressure that isless than about 30 bar.

In some embodiments, the system further comprises a pressure swingadsorption (PSA) unit to remove nitrogen from an exit flow of the one ormore reactors.

In some embodiments, the PSA is located or positioned downstream of oneor more adsorbents in fluid communication with the one or more reactors.

In some embodiments, the PSA unit produces a discharge stream comprisingnitrogen and hydrogen, wherein the discharge stream is supplied to theat least one combustion heater.

In some embodiments, the filtered reactor exit flow comprises less than100 ppm of ammonia.

In some embodiments, the one or more adsorbents are configured toregenerate by exchanging heat with one or more electrical heatersembedded in the one or more adsorbents, an exhaust from the at least onecombustion heater, and/or an exit flow from the one or more reactors.

In some embodiments, the one or more adsorbents are replaceable with oneor more new or regenerated adsorbents.

In some embodiments, the one or more catalysts comprise a support and atleast one metal selected from ruthenium, nickel, rhodium, iridium,cobalt, iron, platinum, chromium, palladium, molybdenum, tantalum, orcopper.

In some embodiments, the one or more catalysts are promoted with atleast one metal selected from Li, Na, K, Rb, Cs, Mg, Ca, Ba, Sr, La, Ce,Pr, Sm, or Gd.

In some embodiments, the support comprises at least one materialselected from Al2O3, MgO, CeO2, ZrO2, La2O3, SiO2, Y2O3, TiO2, SiC,hexagonal BN (boron nitride), BN nanotubes, silicon carbide, one or morezeolites, LaAlO3, CeAlO3, MgAl2O4, CaAl2O4, or one or more carbonnanotubes.

In some embodiments, the first reactor is configured to initiate areforming process for the ammonia.

In some embodiments, the reforming process is initiated using the atleast one electrical heater or an electrical current passed through theone or more catalysts.

In some embodiments, the at least one electrical heater or theelectrical current is deactivated after the reforming process isinitiated.

In some embodiments, the one or more fuel cells consume less than 90% ofthe hydrogen from the one or more reactors, and output one or more exitflows comprising the remaining unconverted hydrogen.

In some embodiments, an operating temperature of the one or morereactors is less than 900° C.

In some embodiments, the system further comprises one or more pumps tosupply the ammonia and increase a flow pressure of the ammonia.

In some embodiments, the system does not produce carbon emissions.

In some embodiments, a fuel reforming or conversion of the one or morereactors is greater than about 90%.

In some embodiments, a fuel heating value to useful electrical energyoutput efficiency of the system is at least about 25% and at most about50%.

In some embodiments, the system further comprises one or more electricalbatteries, one or more DC/DC converters, and one or more motors to powera mobile vehicle.

In some embodiments, the one or more electrical batteries provide powerto startup the system.

In some embodiments, the one or more electrical batteries are configuredto provide power to startup the system by supplying the power to the atleast one electrical heater.

In some embodiments, the system further comprises one or more fuel cellsfor generating power, wherein the power generated using the one or morefuel cells charges the one or more electrical batteries after a startupprocess is initiated or completed.

In some embodiments, the one or more fuel cells provide a substantiallysteady power or load for the mobile vehicle, and the one or morebatteries enable dynamic load following capabilities.

In some embodiments, the mobile vehicle comprises an aerial vehicle, anunmanned aerial vehicle, a maritime or aquatic vehicle, or a terrestrialvehicle.

In some embodiments, the system further comprises one or more fuel cellsfor generating power, wherein the power generated using the one or morefuel cells is supplied to a stationary or non-mobile platform ornetwork.

In some embodiments, the stationary or non-mobile platform or networkcomprises an electrical grid.

In some embodiments, the plurality of heating elements are embedded atleast partially in the one or more reactors.

In another aspect, the present disclosure provides a system comprising:one or more reactors in fluid communication with one or more ammoniasources; and at least one heating element positioned at least partiallywithin the one or more reactors, wherein the one or more reactorscomprise a plurality of channels surrounding the at least one heatingelement to enhance flow field and heating uniformity for ammoniareceived from or provided by the one or more ammonia sources, whereinthe plurality of channels provide a flow path for the ammonia that isadjacent to the at least one heating element to facilitate a transfer ofthermal energy between the at least one heating element and the ammonia.

In some embodiments, the at least one heating element comprises a firstheating element for heating a first portion of the ammonia and a secondheating element for heating a second portion of the ammonia, wherein theplurality of channels comprises (i) a first channel for flowing thefirst portion of the ammonia through the one or more reactors and (ii) asecond channel for flowing the second portion of the ammonia through theone or more reactors.

In some embodiments, the plurality of channels comprise two or morechannels that are fluidically isolated from each other during heating of(i) the first portion of the ammonia using the first heating element and(ii) the second portion of the ammonia using the second heating element.

In some embodiments, the plurality of channels comprise a first channelextending along or around a portion of the first heating element and asecond channel extending along or around a portion of the second heatingelement.

In some embodiments, the at least one heating element comprises anelectrical heater or a combustion heater.

In some embodiments, the first heating element and the second heatingelement comprise a combustion heater.

In some embodiments, the first heating element comprises a combustionheater, and wherein the second heating element comprise an electricalheater.

In some embodiments, the at least one heating element comprises aplurality of combustion heaters configured to operate independently.

In some embodiments, the at least one heating element comprises a hybridheating unit comprising a combustion heater and an electrical heater.

In some embodiments, the combustion heater and the electrical heater arearranged in series.

In some embodiments, the combustion heater and the electrical heater arearranged in parallel.

In some embodiments, the system further comprises one or more catalystsconfigured to decompose or crack the ammonia, wherein the at least oneheating element is configured to heat the one or more catalysts tofacilitate the decomposition or cracking of the ammonia.

In some embodiments, the one or more catalysts are provided outside ofor external to the at least one heating element.

In some embodiments, the at least one heating element comprises one ormore external surfaces, wherein the one or more catalysts are providedadjacent to and/or in thermal communication with the external surfacesof the at least one heating element.

In some embodiments, the one or more catalysts are located or providedwithin the plurality of channels.

In some embodiments, the at least one heating element is configured toprovide a plurality of heating zones within the one or more reactors,wherein the plurality of heating zones have different temperaturesand/or heating profiles.

In some embodiments, the one or more reactors comprise (i) a first flowpath for passage of the ammonia through the one or more reactors forheating of the ammonia using the at least one heating element and (ii) asecond flow path for directing reformate gases produced fromdecomposition or cracking of the ammonia to one or more outlets of theone or more reactors.

In some embodiments, the first flow path and the second flow path areoriented in different directions.

In some embodiments, the first flow path and the second flow path arepositioned adjacent to each other to enable a transfer of thermal energybetween (i) the ammonia entering the one or more reactors and (ii) thereformate gases exiting the one or more reactors.

In some embodiments, the at least one heating element comprises aplurality of heating elements each having one or more dedicated flowchannels for the ammonia, wherein the plurality of channels comprise theone or more dedicated flow channels.

In some embodiments, the at least one heating element is configured to(i) control temperatures and/or heating profiles of different regions ofthe one or more reactors or (ii) adjust a location of one or moreheating zones within the one or more reactors to optimize ammoniathermal reforming efficiency and/or conversion.

In some embodiments, the system further comprises a plurality ofdifferent catalysts for decomposing the ammonia, wherein the pluralityof different catalysts are in thermal communication with the at leastone heating element.

In some embodiments, the plurality of different catalysts comprise afirst catalyst with a first set of ammonia reforming properties and asecond catalyst with a second set of ammonia reforming properties.

In some embodiments, the first catalyst and the second catalyst are inthermal communication with different heating elements.

In some embodiments, the first catalyst and the second catalyst are inthermal communication with different locations or regions of a sameheating element.

In some embodiments, the first catalyst and the second catalyst are inthermal communication with different heating zones generated by the atleast one heating element.

In some embodiments, the one or more channels comprise one or morebaffles to induce turbulence or mixing, increase flow residence time,and/or enhance flow uniformity and heat transfer.

In some embodiments, the system further comprises a controllerconfigured to control a flow of the ammonia into the one or morechannels by modulating one or more flow control units.

In some embodiments, the controller is configured to control the flow ofammonia based on a heating power input to the at least one heatingelement and/or a temperature of the at least one heating element.

In some embodiments, the system further comprises a controllerconfigured to control an operation or a temperature of the at least oneheating element.

In some embodiments, the system further comprises one or more heatexchanger(s) between one or more hot outlet flow(s) and one or more coldinlet flow(s) of the one or more reactors.

In some embodiments, each of the one or more reactors is configured toreform ammonia gas at a rate of at least about 50 L/min STP.

In some embodiments, the system further comprises one or more fuel cellsin fluid communication with the one or more reactors, wherein the one ormore fuel cells are configured to receive and process hydrogen generatedfrom a decomposition of the ammonia to produce electrical energy.

In some embodiments, the system has an energy density of at least about600 Wh/kg, at least about 400 Wh/L, or both.

In some embodiments, the one or more reactors comprise a plurality ofreactors, wherein a first reactor of the plurality of reactors comprisesan electrical heater, and wherein a second reactor of the plurality ofreactors comprises a combustion heater, and wherein the first reactorand the second reactor are in fluidic communication with each other.

In some embodiments, the first reactor and the second reactor arearranged in parallel such that a first exit flow of the first reactorand a second exit flow of the second reactor collectively form acombined exit flow.

In some embodiments, the first reactor and the second reactor arearranged in series so that a first exit flow of the first reactor isconfigured to enter the second reactor.

In some embodiments, the system further comprises one or more fuel cellsin fluid communication with the one or more reactors.

In some embodiments, the system further comprises one or more adsorbentsin fluid communication with the one or more reactors and the one or morefuel cells, wherein the one or more adsorbents are configured to filterout or remove unconverted ammonia from an exit flow from the one or morereactors.

In some embodiments, the one or more adsorbents are configured toprovide a filtered reactor exit flow to the one or more fuel cells.

In some embodiments, the one or more fuel cells are configured to (i)receive the filtered reactor exit flow from the one or more adsorbents,(ii) process the filtered reactor exit flow to generate electricity, and(iii) output a fuel cell exit flow comprising unconverted hydrogen.

In some embodiments, the at least one heating element is in fluidcommunication with the fuel cell exit flow.

In some embodiments, the at least one heating element is configured tocombust the unconverted hydrogen in order to heat one or more catalystsprovided in the one or more reactors.

In some embodiments, the system further comprises a pressure swingadsorption (PSA) unit configured to remove nitrogen from the exit flowof the one or more reactors.

In some embodiments, the PSA is located or positioned downstream of theone or more adsorbents in fluid communication with the one or morereactors.

In some embodiments, the PSA unit produces a discharge stream comprisingnitrogen and hydrogen, wherein the discharge stream is supplied to theat least one heating element.

In some embodiments, the system further comprises one or more heatexchangers.

In some embodiments, the one or more heat exchangers are configured toexchange thermal energy between an exit flow of the one or more reactorsand a flow of the ammonia from the one or more ammonia sources.

In some embodiments, the one or more heat exchangers are configured tofacilitate a transfer of thermal energy between (i) an exit flow of theone or more reactors and (ii) an ambient environment, in order to coolthe exit flow of the one or more reactors.

In some embodiments, the one or more heat exchangers are configured tofacilitate a transfer of thermal energy between (i) a flow of theammonia from the one or more ammonia sources and (ii) one or more fuelcells in fluid communication with the one or more reactors, in order toevaporate the ammonia.

In some embodiments, the one or more heat exchangers are configured tofacilitate a transfer of thermal energy between (i) a flow of theammonia from the one or more ammonia sources and (ii) an ambientenvironment, in order to evaporate the ammonia.

In some embodiments, the at least one heating element is configured tocombust an exit flow from the one or more reactors to generate thermalenergy for heating the one or more reactors.

In some embodiments, the at least one heating element is configured tocombust an exit flow from one or more adsorbents in fluid communicationwith the one or more reactors to generate thermal energy for heating theone or more reactors.

In some embodiments, the at least one heating element is configured tocombust an exit flow from one or more fuel cells in fluid communicationwith the one or more reactors to generate thermal energy for heating theone or more reactors.

In some embodiments, the at least one heating element is positioned inthe one or more catalysts.

In another aspect, the present disclosure provides a system comprising:one or more reactors configured to at least partially decompose ammoniaprovided to the one or more reactors to yield hydrogen, nitrogen, and/orammonia; and one or more fuel cells in fluid communication with the oneor more reactors, wherein the one or more fuel cells are configured toreceive and process the hydrogen to generate electrical energy, whereinthe one or more reactors and the one or more fuel cells are configuredto be mounted on or to an aerial vehicle, wherein the one or more fuelcells are in electrical communication with one or more motors or driveunits of the aerial vehicle to drive the one or more motors or driveunits of the aerial vehicle.

In some embodiments, the one or more reactors and the one or more fuelcells are configured to operate as an ammonia powerpack unit.

In some embodiments, the ammonia powerpack unit has a weight that isless than about 100 kilograms.

In some embodiments, the ammonia powerpack unit has a volume that isless than about 200 liters.

In some embodiments, the ammonia powerpack unit has an energy density ofat least about 600 watt-hours per kilogram or at least about 400watt-hours per liter.

In some embodiments, the one or more reactors comprise a first reactorand a second reactor in fluid communication with the first reactor.

In some embodiments, the first reactor is configured to decompose atleast a portion of the ammonia provided to the one or more reactors toyield hydrogen, nitrogen, and/or ammonia.

In some embodiments, the second reactor is configured to combust atleast a portion of an exit flow from the first reactor to heat orpre-heat the second reactor, wherein the exit flow from the firstreactor comprises hydrogen and at least one of ammonia or nitrogen.

In some embodiments, the system further comprises one or more heatingelements configured to provide thermal energy for at least partiallydecomposing the ammonia.

In some embodiments, the system further comprises one or more catalystsin thermal communication with the one or more heating elements, whereinthe one or more catalysts are configured to facilitate the decomposingof the ammonia.

In some embodiments, the one or more heating elements comprise one ormore electrical heaters and/or combustors.

In some embodiments, the one or more heating elements comprise acombustor in fluid communication with the one or more fuel cells,wherein the combustor is configured to combust an exit flow from the oneor more fuel cells to heat the one or more reactors, wherein the exitflow comprises unconverted hydrogen.

In some embodiments, the system further comprises a controllerconfigured to control a flow of the ammonia provided to the one or morereactors based on a desired power output from the one or more fuelcells.

In some embodiments, the system further comprises one or more adsorbentsin fluid communication with the one or more reactors, wherein the one ormore adsorbents are configured to process an exit flow from the one ormore reactors to filter out or remove ammonia from the exit flow,wherein the exit flow comprises at least hydrogen and/or nitrogen.

In some embodiments, the adsorbents are in fluid communication with theone or more fuel cells, and wherein the adsorbents are configured todirect the hydrogen and/or the nitrogen to the one or more fuel cellsafter filtering out or removing the ammonia from the exit flow of theone or more reactors.

In some embodiments, the one or more fuel cells are in communicationwith an electrical load and/or one or more electrical batteries.

In some embodiments, the one or more fuel cells are configured to supplypower to one or more electrical batteries in communication with anelectrical load.

In some embodiments, the electrical load comprises the one or moremotors or drive units of the aerial vehicle.

In some embodiments, the system further comprises one or more batteriesfor performing a startup of the one or more reactors, electricalpre-heating of the one or more reactors, and/or dynamic load following.

In some embodiments, the startup occurs within about 30 minutes or less.

In some embodiments, the system further comprises an auxiliary batteryfor powering the one or more motors or drive units of the aerialvehicle.

In some embodiments, the system further comprises one or more fuel cellscapable of charging the auxiliary battery during operation.

In some embodiments, the system further comprises one or more heatexchangers for (i) cooling an exit flow of the one or more reactorsand/or (ii) vaporizing or heating a flow of ammonia from one or morefuel storage tanks to the one or more reactors.

In some embodiments, the system further comprises one or more fuelstorage tanks for storing and providing the ammonia to the one or morereactors, wherein the one or more fuel storage tanks are mounted on theaerial vehicle.

In some embodiments, the one or more fuel cells are in thermalcommunication with the one or more fuel storage tanks to facilitate atransfer of thermal energy from the fuel cells to the fuel storage tanksto heat and/or evaporate the ammonia.

In some embodiments, the one or more fuel cells are in thermalcommunication with one or more heat exchangers to facilitate a transferof thermal energy from the fuel cells to the one or more heat exchangersto heat and/or evaporate the ammonia.

In some embodiments, the one or more heat exchangers are in thermalcommunication with an exit flow from the one or more fuel cells to coolthe heat exchangers and/or the exit flow from the one or more reactors.

In some embodiments, the one or more heat exchangers are in thermalcommunication with an ambient environment to cool the one or more heatexchangers.

In some embodiments, the system further comprises a controllerconfigured to modulate (i) a flow of ammonia to the one or more reactorsor (ii) a flow of hydrogen to the one or more fuel cells.

In some embodiments, the controller is configured to provide dynamicpower control by modulating the flow of ammonia or hydrogen.

In some embodiments, each of the one or more reactors is configured todecompose at least about 30 liters of STP ammonia gas per minute.

In some embodiments, the system further comprises one or more sensorsoperatively coupled to the controller, wherein the controller isconfigured to monitor a temperature of the one or more reactors, a flowpressure or a flow rate of the ammonia, a flow pressure or a flow rateof the hydrogen, and/or an electrical output of the one or more fuelcells, based on one or more measurements obtained using the one or moresensors.

In some embodiments, the controller is configured to increase an airsupply unit power to increase an air flow rate to one or more combustorsof the one or more reactors based on a temperature of the one or morereactors.

In some embodiments, the controller is configured to adjust an ammoniaflow pressure to increase an ammonia flow rate and to provide additionalhydrogen to one or more combustors of the one or more reactors based ona temperature of the one or more reactors.

In some embodiments, the controller is configured to increase an ammoniaflow pressure to increase an ammonia flow rate to provide additionalhydrogen to one or more combustors of the one or more reactors based ona temperature of the one or more reactors.

In some embodiments, the controller is configured to modulate one ormore valves in fluid communication with one or more fuel storage tankscomprising the ammonia to maintain or reach a threshold pressure pointcorresponding to a desired ammonia flow rate and power output.

In another aspect, the present disclosure provides a method, comprising:(a) processing ammonia using one or more reactors to produce or generatehydrogen, wherein the one or more reactors comprise (i) one or morecatalysts and (ii) a plurality of heating elements in thermalcommunication with the one or more catalysts, wherein the plurality ofheating elements comprise at least one electrical heater and at leastone combustion heater; and (b) providing the hydrogen to one or morefuel cells to produce electrical energy.

In some embodiments, the one or more reactors comprise a first reactorand a second reactor in fluid communication with the first reactor.

In some embodiments, the first reactor comprises (i) a first catalyst ofthe one or more catalysts and (ii) a startup heating and reforming unitconfigured to heat the first catalyst, wherein the first catalyst isconfigured to produce or extract the hydrogen from the ammonia.

In some embodiments, the startup heating and reforming unit comprisesthe at least one electrical heater.

In some embodiments, the at least one electrical heater comprises one ormore electrodes for passing a current through the first catalyst to heatthe first catalyst.

In some embodiments, the second reactor comprises (i) a second catalystof the one or more catalysts and (ii) one or more main heating unitsconfigured to heat the second catalyst, wherein the second catalyst isconfigured to produce or extract the hydrogen from the ammonia.

In some embodiments, the one or more main heating units comprise the atleast one combustion heater.

In some embodiments, the at least one combustion heater is configured toheat at least a portion of the second catalyst by combusting at leastthe portion of the hydrogen generated using the first reactor.

In some embodiments, the method further comprises, subsequent to (b),providing the electrical energy to an electrical load and/or one or moreelectrical batteries.

In some embodiments, the method further comprises, prior to (b),filtering or removing unconverted ammonia from an exit flow from the oneor more reactors.

In some embodiments, the unconverted ammonia is filtered or removed fromthe exit flow using one or more adsorbents to produce a filtered reactorexit flow.

In some embodiments, the one or more fuel cells are configured to (i)receive the filtered reactor exit flow from the one or more adsorbents,(ii) process the filtered reactor exit flow to generate the electricalenergy, and (iii) output a fuel cell exit flow comprising unconvertedhydrogen.

In some embodiments, the method further comprises combusting theunconverted hydrogen from the one or more fuel cells in order to heatthe one or more catalysts.

In some embodiments, the unconverted hydrogen is combusted using one ormore of the plurality of heating elements.

In some embodiments, the method further comprises combusting an exitflow from the one or more reactors to generate thermal energy forheating the one or more reactors or the one or more catalysts.

In some embodiments, the method further comprises combusting an exitflow from one or more adsorbents in fluid communication with the one ormore reactors to generate thermal energy for heating the one or morereactors or the one or more catalysts.

In some embodiments, the method further comprises using a heat exchangerto facilitate a transfer of thermal energy between (i) an exit flow ofthe one or more reactors and (ii) a flow of the ammonia from one or moreammonia sources.

In some embodiments, the method further comprises using a heat exchangerto facilitate a transfer of thermal energy between (i) a flow of theammonia from one or more ammonia sources and (ii) an exit flow from theone or more fuel cells to evaporate the ammonia.

In some embodiments, the method further comprises using a controller tomodulate an exit flow of the one or more reactors and/or a temperatureof the plurality of heating elements.

In some embodiments, the method further comprises using a controller tomonitor and control (i) a temperature of the one or more reactors, (ii)a flow pressure of the ammonia and/or the hydrogen, and/or (iii) anelectrical output of the one or more fuel cells.

In some embodiments, the method further comprises using a controller tomodulate an air flow rate to the at least one combustion heater, acombustion fuel flow rate to the at least one combustion heater, or boththe air flow rate and the combustion fuel flow rate to the at least onecombustion heater, based on a temperature of the one or more reactors.

In some embodiments, the method further comprises using a controller tomodulate a power output or hydrogen consumption of the one or more fuelcells, based on a temperature of the one or more reactors.

In some embodiments, the method further comprises using a controller tomodulate a flow rate of the ammonia to the one or more reactors, basedon a temperature of the one or more reactors and/or fuel cell poweroutput.

In some embodiments, the method further comprises using a pressure swingadsorption (PSA) unit to remove nitrogen from an exit flow of the one ormore reactors.

In some embodiments, the PSA is located or positioned downstream of oneor more adsorbents in fluid communication with the one or more reactors.

In some embodiments, the PSA unit produces a discharge stream comprisingnitrogen and hydrogen, wherein the discharge stream is supplied to theat least one combustion heater.

In some embodiments, the method further comprises using the firstreactor to initiate a reforming process for the ammonia.

In some embodiments, initiating the reforming process comprisesproviding an electrical current through at least a portion of the one ormore catalysts or at least a portion of the one or more electricalheaters to heat the one or more catalysts and facilitate decompositionor cracking of the ammonia.

In another aspect, the present disclosure provides a system comprising:an ammonia processing unit comprising a plurality of reactors, whereinthe plurality of reactors comprise one or more electrical reactors,wherein the one or more electrical reactors are configured to (i)process ammonia to generate hydrogen and (ii) provide at least a portionof the hydrogen to one or more combustion reactors and/or one or morefuel cells in fluid communication with the one or more electricalreactors and/or the one or more combustion reactors.

In some embodiments, the system further comprises the one or morecombustion reactors.

In some embodiments, the one or more combustion reactors are configuredto combust the hydrogen to heat the one or more combustion reactors to apredetermined threshold temperature.

In some embodiments, the one or more combustion reactors are configuredto (i) process the ammonia to generate one or more combustion reactorexit flows and (ii) provide the one or more combustion reactor exitflows to the one or more fuel cells.

In some embodiments, the one or more combustion reactors comprise one ormore swirl burners configured to mix or swirl (i) a first streamcomprising a combustion fuel with (ii) a second stream comprising air tofacilitate combustion of the combustion fuel in order to heat the one ormore combustion reactors, optionally wherein the combustion fuelcomprises the hydrogen.

In some embodiments, the one or more swirl burners comprise one or moreflow channels for directing the first stream and the second stream alongone or more helical or spiral flow paths to enhance combustion of thefuel.

In some embodiments, the one or more electrical reactors are heated orpreheated using an electrical power source.

In some embodiments, the system further comprises a heat exchangerconfigured to facilitate a transfer of thermal energy between (i) anincoming flow of the ammonia to the ammonia processing unit and (ii) oneor more exit flows from the one or more combustion reactors, in order topreheat and/or evaporate the ammonia.

In some embodiments, the one or more combustion reactors are configuredto (i) heat or preheat the ammonia and (ii) provide the heated orpreheated ammonia to the one or more electrical reactors or one or morecombustion reactors for processing of the ammonia to generate hydrogen.

In some embodiments, the system further comprises the one or more fuelcells.

In some embodiments, the one or more fuel cells are configured toprocess (i) the hydrogen produced by the one or more electrical reactorsand/or (ii) hydrogen produced by the one or more combustion reactors, togenerate electricity.

In some embodiments, the one or more fuel cells are configured toproduce one or more fuel cell exit flows comprising unconvertedhydrogen.

In some embodiments, the one or more combustion reactors are configuredto utilize the unconverted hydrogen as combustion fuel to facilitateammonia decomposition and maintain self-sustained auto-thermalreforming.

In some embodiments, the plurality of reactors are arranged in a seriesconfiguration.

In some embodiments, the plurality of reactors are arranged in aparallel configuration.

In some embodiments, the plurality of reactors are provided in a modularconfiguration.

In some embodiments, the system further comprising a control unitconfigured to control an operation of the ammonia processing unit toregulate a fluid pressure at an inlet of the one or more fuel cells.

In some embodiments, the system further comprises a control unitconfigured to control an operation of the ammonia processing unit toregulate a fluid flow rate to the one or more fuel cells.

In some embodiments, the ammonia processing unit further comprises oneor more valves, pumps, fans, blowers, or compressors for regulating anoutput or an operation of the ammonia processing unit.

In some embodiments, the ammonia processing unit is configured toprocess the ammonia for one or more mobile applications or platforms.

In some embodiments, the ammonia processing unit is configured toprocess the ammonia for one or more stationary applications orplatforms.

In some embodiments, the ammonia processing unit is configured to beattached, coupled, or mounted to a vehicle.

In some embodiments, the ammonia processing unit is configured to beintegrated with one or more electrical or mechanical components of avehicle.

In another aspect, the present disclosure provides a method, comprising:(a) heating an electrical reactor to a first target temperature; (b)reforming ammonia using the electrical reactor to produce a fuelcomprising at least hydrogen; (c) heating a combustion reactor to asecond target temperature by combusting the fuel produced in (b); and(d) providing additional ammonia to the combustion reactor, wherein thecombustion reactor is configured to (i) decompose the additional ammoniato generate additional hydrogen and (ii) provide the additional hydrogento one or more fuel cells.

In some embodiments, the combustion reactor is configured forself-sustaining auto-thermal reforming at the second temperature.

In some embodiments, the method further comprises, subsequent to (c),turning off an electrical heater of the electrical reactor.

In some embodiments, (c) further comprises turning off an electricalheater of the electrical reactor.

In some embodiments, the method further comprises controlling anoperation of the electrical reactor based on a temperature of thecombustion reactor or an ammonia conversion efficiency of the combustionreactor.

In some embodiments, the method further comprises controlling a flowrate of the ammonia to the electrical reactor or the combustion reactorbased on a temperature of the combustion reactor or an ammoniaconversion efficiency of the combustion reactor.

In some embodiments, the method further comprises controlling an exitflow rate from the combustion reactor based on a temperature of thecombustion reactor or an ammonia conversion efficiency of the combustionreactor.

In some embodiments, the method further comprises controlling an airflow rate to the combustion reactor based on a temperature of thecombustion reactor or an ammonia conversion efficiency of the combustionreactor.

In some embodiments, the method further comprises, subsequent to (d),directing an exit flow from the one or more fuel cells to the combustionreactor to facilitate the decomposition of the additional ammonia.

In some embodiments, the exit flow from the one or more fuel cellscomprises unconverted hydrogen.

In some embodiments, the method further comprises controlling an airflow rate or an ammonia flow rate to the combustion reactor to reach ormaintain a predetermined temperature range.

In some embodiments, the method further comprises, prior to (b) and/or(c), preheating the ammonia.

In some embodiments, the ammonia is preheated using the combustionreactor or the electrical reactor.

In some embodiments, the ammonia is preheated using an exit flow fromthe combustion reactor.

In some embodiments, the ammonia is preheated using a combustion productgas.

In some embodiments, heat is exchanged between the ammonia and thecombustion product gas in a counter flow or a parallel flow.

Another aspect of the present disclosure provides a non-transitorycomputer readable medium comprising machine executable code that, uponexecution by one or more computer processors, implements any of themethods above or elsewhere herein.

Another aspect of the present disclosure provides a system comprisingone or more computer processors and computer memory coupled thereto. Thecomputer memory comprises machine executable code that, upon executionby the one or more computer processors, implements any of the methodsabove or elsewhere herein.

In certain aspects, the present disclosure provides a system for ammonia(NH₃) decomposition, comprising: an ammonia reforming reactor and aplurality of heaters. In some embodiments, the ammonia reforming reactorcomprises: a housing comprising a plurality of inner flow paths and anouter flow path, wherein the plurality of inner flow paths is in fluidcommunication with the outer flow path, and one or more NH₃ reformingcatalysts capable of reforming NH₃ to generate a reformate stream,wherein the reformate stream comprises hydrogen and nitrogen, whereinthe one or more NH₃ reforming catalysts are located in at least one of(i) the plurality of inner flow paths or (ii) the outer flow path. Insome embodiments, each inner flow path is configured to be heated by atleast one of the plurality of heaters. In some embodiments, each innerflow path is in thermal communication with the at least one of theplurality of heaters along a length of the inner flow path.

In some embodiments, the one or more NH₃ reforming catalysts comprise: afirst NH₃ reforming catalyst that is configured to contact ammonia at afirst temperature range to generate reformate; and a second NH₃reforming catalyst that is configured to contact the ammonia at a secondtemperature range to generate additional reformate. In some embodiments,the second temperature range is greater than the first temperaturerange. In some embodiments, an ammonia conversion efficiency of thefirst NH₃ reforming catalyst is higher at the first temperature rangecompared to an ammonia conversion efficiency of the second NH₃ reformingcatalyst at the first temperature range.

In some embodiments, the first NH₃ reforming catalyst and the second NH₃reforming catalyst are in thermal communication with different heatersof the plurality of heaters. In some embodiments, the first NH₃reforming catalyst and the second NH₃ reforming catalyst are in thermalcommunication with different heating regions of a same heater of theplurality of heaters. In some embodiments, the first NH₃ reformingcatalyst comprises ruthenium (Ru), platinum (Pt), or palladium (Pd). Insome embodiments, the second NH₃ reforming catalyst comprises nickel(Ni), cobalt (Co), molybdenum (Mo), iron (Fe), or copper (Cu). In someembodiments, each inner flow path is configured to be heated by at leasttwo of the plurality of heaters. In some embodiments, the plurality ofheaters comprises at least one electrical heater. In some embodiments,the plurality of heaters comprises at least one combustion heater. Insome embodiments, the housing comprises a circular cross-sectional shapeor a rectangular cross-sectional shape.

In some embodiments, the system further comprises a plurality of inletsfor directing the NH₃ to the ammonia reforming reactor, wherein one ormore respective inlets of the plurality of inlets is in fluidcommunication with a corresponding respective inner flow path of theplurality of inner flow paths. In some embodiments, the system furthercomprises at least one outlet configured to direct the reformate streamout of the ammonia reforming reactor, wherein the at least one outlet isin fluid communication with the at least one outer flow path. In someembodiments, at least one of the plurality of heaters is configured tocontrol temperatures of different regions of the ammonia reformingreactor based on an ammonia conversion efficiency measured downstream ofthe ammonia reforming reactor. In some embodiments, at least one of theplurality of heaters is configured to adjust a location of a heatingregion in the ammonia reforming reactor based on an ammonia conversionefficiency measured downstream of the ammonia reforming reactor. In someembodiments, the system further comprises a baffle or fin configured toenhance heat transfer in or adjacent to at least one of the plurality ofinner flow paths or the at least one outer flow path. In someembodiments, the system further comprises an ammonia storage tank and afuel cell, wherein the system comprises a volumetric energy density ofgreater than about 400 Watt-hours (Wh) of electricity per liter and lessthan about 3000 Wh of electricity per liter.

The present disclosure also provides a method for NH₃ decomposition,comprising: contacting, in an ammonia reforming reactor, ammonia withone or more NH₃ reforming catalysts capable of reforming NH₃ to generatea reformate stream, wherein the reformate stream comprises hydrogen andnitrogen, wherein the ammonia reforming reactor comprises: (a) a housingcomprising a plurality of inner flow paths and an outer flow path,wherein the plurality of inner flow paths is in fluid communication withthe outer flow path; and (b) a plurality of heaters, wherein each innerflow path is configured to be heated by at least one of the plurality ofheaters, wherein each inner flow path is in thermal communication withthe at least one of the plurality of heaters along a length of the innerflow path, and wherein the one or more NH₃ reforming catalysts arelocated in at least one of (i) the plurality of inner flow paths and(ii) the outer flow path.

In some embodiments, the one or more NH₃ reforming catalysts comprise afirst NH₃ reforming catalyst and a second NH₃ reforming catalyst. Insome embodiments, the ammonia is contacted with the first NH₃ reformingcatalyst at the first temperature range to generate reformate. In someembodiments, the ammonia is contacted with the second NH₃ reformingcatalyst at a second temperature range to generate additional reformate.In some embodiments, the second temperature range is greater than thefirst temperature range. In some embodiments, an ammonia conversionefficiency of the first NH₃ reforming catalyst is higher at the firsttemperature range compared to an ammonia conversion efficiency of thesecond NH₃ reforming catalyst at the first temperature range.

In some embodiments, the first NH₃ reforming catalyst and the second NH₃reforming catalyst are in thermal communication with different heatersof the plurality of heaters. In some embodiments, the first NH₃reforming catalyst and the second NH₃ reforming catalyst are in thermalcommunication with different heating regions of a same heater of theplurality of heaters. In some embodiments, the first NH₃ reformingcatalyst comprises ruthenium (Ru), platinum (Pt), or palladium (Pd). Insome embodiments, the second NH₃ reforming catalyst comprises nickel(Ni), cobalt (Co), molybdenum (Mo), iron (Fe), or copper (Cu). In someembodiments, the plurality of heaters comprises at least one electricalheater. In some embodiments, the plurality of heaters comprises at leastone combustion heater. In some embodiments, the housing comprises acircular cross-sectional shape or a rectangular cross-sectional shape.

In some embodiments, the method further comprises directing the NH₃ tothe ammonia reforming reactor using a plurality of inlets, wherein oneor more respective inlets of the plurality of inlets is in fluidcommunication with a corresponding respective inner flow path of theplurality of inner flow paths. In some embodiments, the method furthercomprises directing the reformate stream out of the ammonia reformingreactor using at least one outlet, wherein the at least one outlet is influid communication with the at least one outer flow path. In someembodiments, the method further comprises using at least one of theplurality of heaters, controlling temperatures of different heatingregions of the ammonia reforming reactor based on an ammonia conversionefficiency measured downstream of the ammonia reforming reactor. In someembodiments, the method further comprises using at least one of theplurality of heaters, adjusting a location of a heating region in theammonia reforming reactor based on an ammonia conversion efficiencymeasured downstream of the ammonia reforming reactor. In someembodiments, the method further comprises using a baffle or fin toenhance heat transfer in or adjacent to at least one of the plurality ofinner flow paths or the at least one outer flow path.

Additional aspects and advantages of the present disclosure will becomereadily apparent to those skilled in this art from the followingdetailed description, wherein only illustrative embodiments of thepresent disclosure are shown and described. As will be realized, thepresent disclosure is capable of other and different embodiments, andits several details are capable of modifications in various obviousrespects, all without departing from the disclosure. Accordingly, thedrawings and description are to be regarded as illustrative in nature,and not as restrictive.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.To the extent publications and patents or patent applicationsincorporated by reference contradict the disclosure contained in thespecification, the specification is intended to supersede and/or takeprecedence over any such contradictory material.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings (also “Figure” and “FIG.” herein), of which:

FIG. 1 schematically illustrates an exemplary system for processingammonia to generate hydrogen fuel, in accordance with one or moreembodiments of the present disclosure.

FIG. 2 schematically illustrates an exemplary method of hydrogen storageusing liquid chemicals, in accordance with one or more embodiments ofthe present disclosure.

FIG. 3 schematically illustrates using ammonia as a hydrogen carrier, inaccordance with one or more embodiments of the present disclosure.

FIG. 4 schematically illustrates ammonia as an energy carrier andvarious density characteristics of ammonia in comparison to other typesof fuel.

FIG. 5 schematically illustrates a power system using ammonia as a fuelfor fuel cells, in accordance with one or more embodiments of thepresent disclosure. In one or more embodiments of the presentdisclosure, the power system may comprise a proton-exchange membranefuel cell (PEMFC)

FIG. 6 schematically illustrates a system architecture for an exemplaryammonia power pack, in accordance with one or more embodiments of thepresent disclosure.

FIG. 7A schematically illustrates an example of an electrically heatedfast startup reactor, in accordance with one or more embodiments of thepresent disclosure.

FIG. 7B schematically illustrates an example of an electrically heatedfast startup reactor comprising one or more electrically conductivesprings, in accordance with one or more embodiments of the presentdisclosure.

FIG. 8 schematically illustrates a plot of gas temperature as a functionof time for a fast startup reactor comprising one or more electricallyconductive springs, in accordance with one or more embodiments of thepresent disclosure.

FIG. 9 schematically illustrates various enhancements and treatments forcatalyst materials that may be used for the fast startup reactor, inaccordance with one or more embodiments of the present disclosure.

FIG. 10 schematically illustrates startup time simulation data for thestartup reactor, in accordance with one or more embodiments of thepresent disclosure.

FIG. 11 schematically illustrates ammonia conversion simulation data forthe startup reactor, in accordance with one or more embodiments of thepresent disclosure.

FIG. 12 schematically illustrates an example of a modular design for thestartup reactor, in accordance with one or more embodiments of thepresent disclosure.

FIG. 13 schematically illustrates transient time and transient reactortemperature data for the startup reactor, in accordance with one or moreembodiments of the present disclosure.

FIG. 14 schematically illustrates an example of a main reactor withhybrid heating, in accordance with one or more embodiments of thepresent disclosure.

FIGS. 15A and 15B schematically illustrate reactor thermal reformingefficiency, endothermicity fraction, hydrogen combustion fraction, andpower output fuel cell data for the present systems and methods, inaccordance with one or more embodiments of the present disclosure.

FIG. 16 schematically illustrates hybrid heating simulation data for thepresent systems and methods, in accordance with one or more embodimentsof the present disclosure.

FIG. 17 schematically illustrates heating power ratio simulation datafor the present systems and methods, in accordance with one or moreembodiments of the present disclosure.

FIG. 18 schematically illustrates a computer system that is programmedor otherwise configured to implement the present system and methods, inaccordance with one or more embodiments of the present disclosure.

FIGS. 19 - 25 schematically illustrate various examples of systemarchitectures for ammonia processing and ammonia powerpack systems, inaccordance with one or more embodiments of the present disclosure.

FIGS. 26 - 35 schematically illustrate various exemplary configurationsfor packaging and assembly of ammonia powerpack systems, in accordancewith one or more embodiments of the present disclosure.

FIGS. 36A to 36C schematically illustrate configurations for supplyingcombustible hydrogen gas to a combustor, in accordance with one or moreembodiments of the present disclosure.

FIGS. 37A to 37C schematically illustrate configurations for supplyingair to a combustor, in accordance with one or more embodiments of thepresent disclosure.

FIGS. 38A and 38B schematically illustrate combustor designs forcontacting air and fuel, in accordance with one or more embodiments ofthe present disclosure.

FIG. 39 schematically illustrates a combustor design with multiple airand fuel contacts, in accordance with one or more embodiments of thepresent disclosure.

FIGS. 40A and 40B schematically illustrate an outside view and an insidecross-sectional view of a combustor and reactor design, in accordancewith one or more embodiments of the present disclosure.

FIG. 40C schematically illustrates a system comprising a combustorconfigured for combustion inside a reactor, in accordance with one ormore embodiments of the present disclosure.

FIG. 40D shows a photograph of a system comprising a combustorconfigured for combustion inside a reactor, in accordance with one ormore embodiments of the present disclosure.

FIGS. 41A and 41B show experimental measurements of reactor thermalreforming efficiency and combustor efficiency as a function of NH₃ flowrate, conducted with the design shown in FIG. 40C.

FIG. 42 schematically illustrates a design comprising two combustorspartially embedded within a reactor, in accordance with one or moreembodiments of the present disclosure.

FIG. 43 shows a temperature profile of a combustor design solved with asimulation, in accordance with one or more embodiments of the presentdisclosure.

FIG. 44 shows a temperature profile of a combustor design solved with asimulation, in accordance with one or more embodiments of the presentdisclosure.

FIGS. 45A and 45B show a temperature profile of a combustor designsolved with a simulation, in accordance with one or more embodiments ofthe present disclosure.

FIGS. 46A and 46B show a temperature profile and a hydrogen mass profileof a combustor design solved with a simulation, in accordance with oneor more embodiments of the present disclosure.

FIG. 47 schematically illustrates an exemplary design for a combustorand a reactor, in accordance with one or more embodiments of the presentdisclosure.

FIG. 48 schematically illustrates an exemplary design for a combustorand a reactor, in accordance with one or more embodiments of the presentdisclosure.

FIG. 49 schematically illustrates an example of a system architecturalconfiguration for an ammonia processing system, in accordance with oneor more embodiments of the present disclosure.

FIG. 50 shows a digital rendition of an ammonia powerpack system, inaccordance with one or more embodiments of the present disclosure.

FIG. 51 shows a digital rendition of an ammonia powerpack system mountedon an aerial vehicle, in accordance with one or more embodiments of thepresent disclosure.

FIG. 52 shows an ammonia powerpack system mounted on an aerial vehicle,in accordance with one or more embodiments of the present disclosure.

FIG. 53 shows an aerial vehicle in flight while being powered by anammonia powerpack system, in accordance with one or more embodiments ofthe present disclosure.

FIG. 54 shows a power profile of an aerial vehicle comprising an ammoniapowerpack system, in accordance with one or more embodiments of thepresent disclosure.

FIGS. 55A and 55B schematically illustrate an outside view and an insideview of a reactor with a circular cross-section, in accordance with oneor more embodiments of the present disclosure.

FIG. 56 schematically illustrates a top view and an inside view of areactor with a circular cross-section, in accordance with one or moreembodiments of the present disclosure.

FIGS. 57A and 57B schematically illustrate an outside view and an insideview of a reactor with a square cross-section, in accordance with one ormore embodiments of the present disclosure.

FIGS. 58A and 58B schematically illustrate a top view and an inside viewof a reactor with a square cross-section, in accordance with one or moreembodiments of the present disclosure.

FIGS. 59A and 59B schematically illustrate an outside view and an insideview of a reactor having both high-temperature efficient catalysts andlow-temperature efficient catalysts, in accordance with one or moreembodiments of the present disclosure.

FIG. 60 schematically illustrates a gas flow path in a flow channel of areactor, in accordance with one or more embodiments of the presentdisclosure.

FIG. 61 shows digital renditions of reactors having various shapes andconfigurations, in accordance with one or more embodiments of thepresent disclosure.

FIGS. 62A - 62D show digital renditions of various reactor designshaving different dimensions, in accordance with one or more embodimentsof the present disclosure.

FIGS. 63A and 63B schematically illustrate reactor thermal reformingefficiency and ammonia conversion as a function of ammonia flow ratethrough a reactor, in accordance with one or more embodiments of thepresent disclosure.

FIGS. 64A and 64B schematically illustrates a system configuration forprocessing ammonia during startup and operation, in accordance with oneor more embodiments of the present disclosure.

FIG. 65 schematically illustrates a system configuration for processingammonia during startup, in accordance with one or more embodiments ofthe present disclosure.

FIG. 66 schematically illustrates a system configuration for processingammonia during operation, in accordance with one or more embodiments ofthe present disclosure.

FIG. 67 schematically illustrates an example of a system reactor and/orhotbox configuration, in accordance with one or more embodiments of thepresent disclosure.

FIG. 68 schematically illustrates an example of a system reactor and/orhotbox configuration, in accordance with one or more embodiments of thepresent disclosure.

FIG. 69 schematically illustrates an example of a system reactor and/orhotbox configuration, in accordance with one or more embodiments of thepresent disclosure.

FIG. 70 schematically illustrates an example of a system reactor and/orhotbox configuration during startup, in accordance with one or moreembodiments of the present disclosure.

FIG. 71 schematically illustrates an example of a system reactor and/orhotbox configuration during startup, in accordance with one or moreembodiments of the present disclosure.

FIG. 72 schematically illustrates an example of a system reactor and/orhotbox configuration during operation, in accordance with one or moreembodiments of the present disclosure.

FIG. 73 schematically illustrates an example of a system reactor and/orhotbox configuration during operation, in accordance with one or moreembodiments of the present disclosure.

FIG. 74 shows a combustion burner head design, in accordance with one ormore embodiments of the present disclosure.

FIGS. 75A-75B show a burner head design, in accordance with one or moreembodiments of the present disclosure.

FIGS. 76A-76B show a burner head design, in accordance with one or moreembodiments of the present disclosure.

FIG. 77 shows flow simulations in a combustion tube with a burner head,in accordance with one or more embodiments of the present disclosure.

FIG. 78 shows flow simulations in a combustion tube with a burner head,in accordance with one or more embodiments of the present disclosure.

FIG. 79 shows flow simulations in a combustion tube with a burner head,in accordance with one or more embodiments of the present disclosure.

FIG. 80A shows a powerpack, in accordance with one or more embodimentsof the present disclosure.

FIG. 80B schematically illustrates a tractor having a mounted powerpack,in accordance with one or more embodiments of the present disclosure.

FIGS. 81A-81B show voltage versus current and power versus current,respectively, for an integrated powerpack with a fuel cell.

FIG. 82 shows a block diagram for system control using a controller, inaccordance with one or more embodiments of the present disclosure.

FIG. 83 shows a process flow diagram for a startup process, inaccordance with one or more embodiments of the present disclosure.

FIG. 84 shows a process flow diagram for a startup process, inaccordance with one or more embodiments of the present disclosure.

FIG. 85 shows a process flow diagram for a startup process, inaccordance with one or more embodiments of the present disclosure.

FIG. 86 shows a process flow diagram for a startup process, inaccordance with one or more embodiments of the present disclosure.

FIG. 87 shows a process flow diagram for a post-startup operationprocess, in accordance with one or more embodiments of the presentdisclosure.

FIG. 88 shows a process flow diagram for a post-startup operationprocess, in accordance with one or more embodiments of the presentdisclosure.

DETAILED DESCRIPTION

While various embodiments of the invention have been shown and describedherein, it will be obvious to those skilled in the art that suchembodiments are provided by way of example only. Numerous variations,changes, and substitutions may occur to those skilled in the art withoutdeparting from the invention. It should be understood that variousalternatives to the embodiments of the invention described herein may beemployed.

Whenever the term “at least,” “greater than,” or “greater than or equalto” precedes the first numerical value in a series of two or morenumerical values, the term “at least,” “greater than” or “greater thanor equal to” may apply to each of the numerical values in that series ofnumerical values. For example, greater than or equal to 1, 2, or 3 maybe equivalent to greater than or equal to 1, greater than or equal to 2,or greater than or equal to 3.

Whenever the term “no more than,” “less than,” or “less than or equalto” precedes the first numerical value in a series of two or morenumerical values, the term “no more than,” “less than,” or “less than orequal to” may apply to each of the numerical values in that series ofnumerical values. For example, less than or equal to 3, 2, or 1 may beequivalent to less than or equal to 3, less than or equal to 2, or lessthan or equal to 1.

The term “at least one of A and B” and “at least one of A or B” may beunderstood to mean only A, only B, or both A and B. The term “A and/orB” may be understood to mean only A, only B, or both A and B.

The term “real time” or “real-time,” as used interchangeably herein,generally refers to an event (e.g., an operation, a process, a method, atechnique, a computation, a calculation, an analysis, a visualization,an optimization, etc.) that may be performed using recently obtained(e.g., collected or received) data. In some cases, a real time event maybe performed almost immediately or within a short enough time span, suchas within at least 0.0001 millisecond (ms), 0.0005 ms, 0.001 ms, 0.005ms, 0.01 ms, 0.05 ms, 0.1 ms, 0.5 ms, 1 ms, 5 ms, 0.01 seconds, 0.05seconds, 0.1 seconds, 0.5 seconds, 1 second, or more. In some cases, areal time event may be performed almost immediately or within a shortenough time span, such as within at most 1 second, 0.5 seconds, 0.1seconds, 0.05 seconds, 0.01 seconds, 5 ms, 1 ms, 0.5 ms, 0.1 ms, 0.05ms, 0.01 ms, 0.005 ms, 0.001 ms, 0.0005 ms, 0.0001 ms, or less.

The terms “decompose,” “dissociate,” “reform,” “crack,” and “breakdown,” and their grammatical variations, may be construedinterchangeably. For example, the expression “decomposition of ammonia”may be interchangeable with “dissociation of ammonia,” “reforming ofammonia,” “cracking of ammonia,” etc.

The terms “heater,” “heating element,” and “heating unit,” and theirgrammatical variations, may be construed interchangeably. For example,the expression “electrical heater” may be interchangeable with“electrical heating unit,” “electrical heating element,” etc.

The terms “combustion heater” and “combustor,” and their grammaticalvariations, may be construed interchangeably.

The terms “reactor,” “reformer,” and “reactor module,” and theirgrammatical variations, may be construed interchangeably. For example,the expression “electrical reactor” may be interchangeable with“electrical reactor module.”

The terms “combustion reactor,” “combustion heated reactor,” “combustorreactor,” and “C-reactor,” and their grammatical variations, may beconstrued interchangeably.

The terms “electrical reactor,” “electrically heated reactor,” and“E-reactor,” and their grammatical variations, may be construedinterchangeably.

The terms “controller” and “control unit,” and their grammaticalvariations, may be construed interchangeably.

The terms “ammonia conversion,” “ammonia conversion rate,” and “ammoniaconversion efficiency,” and their grammatical variations, may beconstrued as a fraction of ammonia that is converted to hydrogen andnitrogen, and may be construed interchangeably. For example, “ammoniaconversion,” “ammonia conversion rate,” or “ammonia conversionefficiency” of 90% may represent 90% of ammonia being converted tohydrogen and nitrogen.

The term “auto-thermal reforming” may be construed as a condition wherean ammonia decomposition reaction (2NH₃ → N₂ + 3H₂; an endothermicreaction) is heated by a hydrogen combustion reaction (2H₂ + O₂ → 2H₂O;an exothermic reaction) using at least part of the hydrogen produced bythe ammonia decomposition reaction itself. In some cases, the term“auto-thermal reforming” may be construed as a condition where anammonia decomposition reaction is heated by a hydrogen combustionreaction using at least part of hydrogen produced by the ammoniadecomposition reaction itself, electrical heating, or a combination ofboth, which may result in an overall positive electrical and/or chemicalenergy output. For example, if “auto-thermal reforming” is performedusing a hydrogen combustion reaction and/or electrical heating, thehydrogen produced from the ammonia decomposition reaction may be enoughto provide the hydrogen combustion reaction with combustion fuel, and/orto provide electrical energy for the electrical heating viahydrogen-to-electricity conversion devices (e.g., fuel cell, combustionengine, etc.). In some cases, the hydrogen provided for the hydrogencombustion reaction and/or electricity provided for the electricalheating to perform “auto-thermal reforming” may or may not use thehydrogen from the ammonia decomposition reaction (for example, thehydrogen may be provided by a separate hydrogen source, the electricitymay be provided from batteries or a grid, etc.). In some cases,“auto-thermal reforming” may be construed as a condition where anammonia decomposition reaction is heated by a combustion reaction (e.g.,ammonia combustion, hydrocarbon combustion, etc.), electrical heating,or a combination of both, which may result in an overall positiveelectrical and/or chemical energy output. For example, if “auto-thermalreforming” is performed using a combustion reaction and/or electricalheating, the chemical energy (e.g., lower heating value) from thehydrogen produced from the ammonia decomposition reaction may be higherthan the combustion fuel chemical energy (e.g., lower heating value),and/or may be enough to provide electrical energy for the electricalheating via hydrogen-to-electricity conversion devices (e.g., fuel cell,combustion engine, etc.).

Reactor

In an aspect, the present disclosure provides a system for processing asource material. The system may comprise a reactor or a reformer. Thesource material may be processed to generate a fuel source. The fuelsource may comprise, for example, hydrogen and/or nitrogen. The fuelsource may be provided to one or more hydrogen fuel cells with one ormore air intakes, which may be configured to use the fuel source togenerate electrical energy. Such electrical energy may be used to powervarious systems, vehicles, and/or devices.

Additionally or alternatively, the fuel source may be provided to one ormore internal combustion engines (ICEs), which may be configured toconsume the fuel source to generate mechanical energy (to power adrivetrain, propeller, or other propulsion device) and/or electricalenergy (to power a grid or battery). The fuel source may be provided toan ICE in combination with another fuel such that the ICE operates as adual-fuel (DF) engine. For example, the DF ICE may combust hydrogen withammonia, hydrogen with diesel, hydrogen with natural gas, etc.

FIG. 1 schematically illustrates a block diagram of an exemplary methodfor processing a source material to produce electrical energy, inaccordance with one or more embodiments of the present disclosure. Asource material 110 may be provided to a reactor 120. The sourcematerial 110 may be a compound comprising one or more hydrogen atoms.The compound may be, for example, ammonia (NH3). In some cases, thecompound may comprise a hydrocarbon C_(x)H_(y). The source material 110may be provided to a reactor 120. The source material 110 may be in agaseous state and/or a liquid state. The reactor 120 may be designed orconfigured to process the source material 110 to extract, produce, orrelease a fuel source 130 from the source material 110. In some cases,processing the source material 110 may comprise heating the sourcematerial 110 using the systems and methods of the present disclosure toextract, produce, or release the fuel source 130. The fuel source 130may comprise hydrogen and/or nitrogen. The fuel source 130 may beprovided to one or more fuel cells for the generation of electricalenergy. Such electrical energy may be used to power various systems,vehicles, and/or devices, including, for example, terrestrial, aerial,or aquatic vehicles.

As described above, one or more fuel cells may be used to generateelectrical energy from the fuel source 130, which may comprise hydrogenand/or nitrogen. In some cases, the one or more fuel cells may generateelectricity through an electrochemical reaction between the fuel source130 and oxygen (O₂). The fuels may comprise the hydrogen and/or thenitrogen in the fuel source 130. The electricity generated by the fuelcells may be used to power one or more systems, vehicles, or devices. Insome embodiments, excess electricity generated by the fuel cells may bestored in one or more energy storage units (e.g., batteries) for futureuse. In some optional embodiments, the fuel cells may be provided aspart of a larger electrochemical system. The electrochemical system mayfurther comprise an electrolysis module. Electrolysis of a byproduct ofthe one or more fuel cells (e.g., water) may allow the byproduct to beremoved by decomposing the byproduct into one or more constituentelements (e.g., oxygen and/or hydrogen). Electrolysis of the byproductmay also generate additional fuel (e.g., hydrogen) for the one or morefuel cells. In some embodiments, the one or more fuel cells may operateas a plurality of fuel cells (i.e., an array of fuel cells) such thatthe output power is scalable (e.g., to 50 kilowatts, 500 kilowatts, orseveral megawatts). In any of the embodiments described herein, the oneor more fuel cells may be configured to receive hydrogen from a hydrogensource. The hydrogen source may comprise one or more reactors orreformers as described elsewhere herein. In some non-limitingembodiments, the hydrogen source may not or need not comprise a reactoror a reformer. For example, the hydrogen source may comprise a hydrogenstorage tank. The hydrogen storage tank may or may not be fluidicallyconnected to a reactor or a reformer. In some cases, the hydrogen sourcemay comprise a hydrogen generation system or subsystem. In any of theembodiments described herein, the one or more fuel cells may beconfigured to output electrical energy and/or provide an exit flow toone or more reactors, reformers, heat exchangers, or any othercomponents of the systems described herein to facilitate an ammoniadecomposition process, regardless of the type of hydrogen source used toprovide or supply hydrogen to the one or more fuel cells.

FIG. 2 schematically illustrates an exemplary method of hydrogen storageusing liquid chemicals, in accordance with one or more embodiments ofthe present disclosure. Hydrogen, whether produced by electrolysis ofrenewables (e.g., green hydrogen) or through hydrocarbon reforming(e.g., blue hydrogen or grey hydrogen), may be stored using one or moreliquid chemicals. In some non-limiting embodiments, the one or moreliquid chemicals may comprise, for example, ammonia, a liquid organichydrogen carrier (LOHC), formic acid (HCOOH), or methanol (CH₃OH). Theone or more liquid chemicals may be stored in a hydrogen-rich form or ahydrogen-lean form. The one or more liquid chemicals comprising thehydrogen may be processed as described elsewhere herein to release thehydrogen stored in the liquid chemicals. Once released, the hydrogen maybe used for power generation (e.g., stationary or portable powergeneration), or may be provided to a hydrogen fueling station.

FIG. 3 schematically illustrates using ammonia as a hydrogen carrier, inaccordance with one or more embodiments of the present disclosure.Hydrogenation may be used to store the hydrogen in the one or moreliquid chemicals. Hydrogenation may refer to the treatment of materialsor substances with molecular hydrogen (H₂) to add one or more pairs ofhydrogen atoms to various constituent compounds (e.g., one or moreunsaturated compounds) making up the materials or substances.Hydrogenation may be performed using a catalyst, which may enable thereaction to occur under conditions closer to standard temperature andpressure (e.g., room temperature and sea-level atmospheric pressure). Insome cases, the Haber-Bosch process (an artificial nitrogen fixationprocess) may be used to produce ammonia. The process may be used toconvert atmospheric nitrogen (N₂) to ammonia (NH₃) by a reaction withhydrogen (e.g., H₂ produced or obtained by electrolysis) using a metalcatalyst under high temperatures and pressures: 2NH₃ ↔ N₂ + 3H₂

As described above, the Haber-Bosch process may be used to produceammonia, which can be used as a hydrogen carrier. Using ammonia as ahydrogen carrier may provide several benefits over storing andtransporting pure hydrogen, including easy storage at relativelystandard conditions (0.8 MPa, 20° C. in liquid form), and convenienttransportation. Ammonia also has a relatively high hydrogen content(17.7 wt % or 120 grams of H₂ per liter of liquid ammonia). Further, theproduction of ammonia using the Haber-Bosch process can be powered byrenewable energy sources (e.g., solar photovoltaic, solar-thermal, windturbines, and/or hydroelectricity), which makes the production processenvironmentally safe and friendly, as N₂ is the only byproduct and thereis no further emission of CO₂. Once the ammonia is produced, the ammoniamay be processed to release the hydrogen through a dehydrogenationprocess (i.e., by dissociating, decomposing, reforming, or cracking theammonia). The released hydrogen may then be provided to one or more fuelcells, such as a proton-exchange membrane fuel cell (PEMFC) having aproton-conducting polymer electrolyte membrane (i.e., a polymerelectrolyte membrane [PEM] fuel cell). PEMFCs may have relatively lowoperating temperatures and/or pressure ranges (e.g., from about 50 to100° C.). A proton exchange membrane fuel cell can be used to transformthe chemical energy liberated during the electrochemical reaction ofhydrogen and oxygen into electrical energy, as opposed to the directcombustion of hydrogen and oxygen gases to produce thermal energy.PEMFCs can generate electricity and operate on the opposite principle toPEM electrolysis, which consumes electricity. In some embodiments, theone or more fuel cells may be a solid oxide fuel cell (SOFC), ahigh-temperature PEM (HTPEM), or an alkaline fuel cell (AFC). Themethods and systems disclosed herein may be implemented to achievethermally efficient hydrogen production, and may be scaled forapplication to high energy density power systems.

FIG. 4 schematically illustrates ammonia as an energy carrier andvarious density characteristics of ammonia in comparison to other typesof fuel. The H₂ storage capacity of NH₃ is about 17.7 wt % and 120 gramsof H₂ per liter of ammonia. Compared to other fuel types such ashydrogen, ammonia exhibits a favorable volumetric density in view of itsgravimetric density. Further, in comparison to other types of fuel(including carbon-based fuels such as methane, propane, methanol,ethanol, gasoline, E-10 gasoline, JP-8 jet fuel, or diesel), the use ofammonia as a fuel may not produce harmful emissions such as CO₂, CO, orblack carbon (soot), and may produce zero or negligible NO_(x) (e.g.,NO₂ or N₂O) emissions (especially in combination with a selectivecatalytic reduction [SCR] catalyst). Thus, the use of ammonia as anenergy carrier allows some embodiments of the presently disclosedsystems and methods to leverage the benefits of hydrogen fuel (e.g.,environmentally safe and high gravimetric energy density) once theammonia is decomposed into hydrogen, while taking advantage of (a)ammonia’s greater volumetric density compared to hydrogen and (b) theability to transport ammonia at standard temperatures and pressureswithout requiring the complex and highly pressurized storage vesselstypically used for storing and transporting hydrogen.

In some cases, ammonia may be comprised or stored in a liquid fuelstorage tank. In some cases, ammonia may be stored as liquid ammonia. Insome cases, the liquid ammonia may be stored at a temperature rangingfrom about 15 to about 30° C. and at an absolute pressure ranging from 7to 12 bar. In some cases, the liquid ammonia may be stored at a gaugepressure ranging from about atmospheric pressure to about 20 bar. Insome cases, the liquid ammonia may be stored at a temperature rangingfrom about -40 to about 20° C. and at an absolute pressure ranging fromabout 0.5 bar to about 9 bar. In some cases, the liquid ammonia may bestored at a temperature of at least about -60, -50, 40, -30, -20, -10,0, 10, 20, 30, 40, 50, or 60 degree Celsius. In some cases, the liquidammonia may be stored at a temperature of at most about -60, -50, 40,-30, -20, -10, 0, 10, 20, 30, 40, 50, or 60 degree Celsius. In somecases, the liquid ammonia may be stored at an absolute pressure of atleast about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, or 40bar. In some cases, the liquid ammonia may be stored at an absolutepressure of at most about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30,35, 40, 45, or 50 bar.

FIG. 5 schematically illustrates a power system using ammonia as a fuelsource to generate hydrogen, which may be provided to one or more fuelcells (e.g., proton-exchange membrane fuel cells [PEMFCs]) to generateelectrical energy, in accordance with one or more embodiments of thepresent disclosure. The power system may comprise a reformer configuredto perform a catalytic decomposition or cracking of ammonia to extractand/or produce hydrogen. Such a reformer may be operated using heatenergy. In some cases, the power system may comprise a combustor thatgenerates heat energy to drive the operation of the reformer. In somecases, the heat energy may be generated from the combustion of achemical compound (e.g., hydrogen or a hydrocarbon). The hydrogen thatis generated and/or extracted using the reformer may be provided to oneor more fuel cells, which may produce electrical energy to power one ormore systems, sub-systems, or devices requiring electrical energy tooperate. In some cases, the hydrogen generated and/or extracted usingthe reformer may be provided to one or more other reactors or reformers.In such cases, the one or more other reactors or reformers may beconfigured to combust the hydrogen to generate thermal energy. Suchthermal energy may be used to heat the one or more other reactors orreformers to facilitate a further catalytic decomposition or cracking ofammonia to extract and/or produce additional hydrogen.

Fast Startup Reactor Module

In some embodiments, the systems of the present disclosure may comprisea power pack and a load following module. The power pack and loadfollowing module may facilitate heat transfer for the catalyst, fasterreactor start-up times, and optimized thermal management, packagingoptimization, and dynamic load following. In some cases, the power packmay comprise a load following module that enables fast startup. Suchload following module may be integrated with one or more structuralelements or subsystems of the power pack. The load following reactorsdescribed herein may be configured to adjust power output (e.g. of afuel cell) based on a demand for power (e.g., at an electrical loadcoupled to the fuel cell), and may adjust power output fast enough toavoid the use of an extra battery system. Such demand may be determinedbased on feedback provided by one or more end users operating a systemor a device that requires power, or based on one or more sensor readingsindicating a lack of sufficient power or a need for additional power.The one or more sensor readings may be obtained using one or moresensors provided on or operatively coupled to a system or device that isoperated using electrical energy generated by one or more fuel cells(that consume hydrogen produced by the reactors).

FIG. 6 schematically illustrates a system architecture for an exemplaryammonia power pack, in accordance with one or more embodiments of thepresent disclosure. The system architecture may comprise a power packand a load following module as described above. In some cases, thesystem may have a system level energy density of at least about 600watt-hours per kilogram. In some cases, the system may have a hydrogenstorage capacity of at least about 5% by weight. The system illustratedin FIG. 6 may comprise a startup reactor R_s. Ammonia may be provided tothe startup reactor via one or more fuel lines. The flow of ammonia tothe startup reactor may be controlled using one or more flow controlunits FCU and/or one or more valves SV (e.g., a solenoid valve). Thestartup reactor R_s may be configured to heat up a catalyst directlyusing resistance heating (i.e., by passing current through the catalystitself or through the catalyst support). This particular configurationmay reduce thermal mass and generate heat where one or more reactionsoccur, which may reduce the startup times needed to reach the desiredreaction temperatures for ammonia decomposition. In some embodiments,the desired temperature may range from about 400° Celsius to about 600°Celsius. The heat generated using the startup reactor R_s may be used toheat up the catalyst or a portion thereof. The heat generated using thestartup reactor R_s may also be used to decompose or crack a portion ofthe ammonia to generate hydrogen, which may be directly provided to oneor more fuel cells for the generation of electricity. In some cases, thehydrogen generated from decomposing the ammonia may be combusted to heatup the main reactor R_m. In some cases, the heat generated using thestartup reactor R_s may be used to heat up the main reactor R_m or aportion thereof. In such cases, the startup reactor R_s and the mainreactor R_m may be in thermal communication with each other to enable atransfer of heat energy between the two reactors. The main reactor R_mmay comprise one or more heating units. The one or more heating unitsmay comprise, for example, an electrical heater and/or a combustionheater. The heat generated using the startup reactor R_s may be used tosupplement the heat generated using the electrical heater and/or thecombustion heater of the main reactor R_m. The main reactor R_m may beconfigured to use the heat generated using the electrical heater, thecombustion heater, the startup reactor R_s, and/or the combustion of anyhydrogen produced using the startup reactor R_s to decompose the ammoniaprovided to the system to generate and/or extract hydrogen from theammonia. The extracted hydrogen may be provided to one or more fuelcells FC for the generation of electrical energy. In some cases, anadsorption tower ADS may be used to process (e.g., refine or purify) thehydrogen before the hydrogen is provided to the one or more fuel cells.The electricity produced using the hydrogen and the one or more fuelcells may be used to power an electric load (e.g., an aerial vehiclesuch as a drone or aircraft).

In some cases, the main reactor R_m and the startup reactor R_s may beconfigured to receive ammonia from a same source. The same source may bein fluid communication with both the main reactor R_m and the startupreactor R_s (e.g., via separate piping, ducting, or flow channels).Alternatively, the same source may be in fluid communication with themain reactor R_m via the startup reactor R_s, or the startup reactor R_svia the main reactor R_m. In other cases, the main reactor R_m and thestartup reactor R_s may be configured to receive ammonia from differentsources. In such cases, the main reactor R_m may be configured toreceive ammonia from a first source, and the startup reactor R_s may beconfigured to receive ammonia from a second source. The first source andthe second source may or may not be in fluid communication with oneanother. In some cases, the main reactor R_m and/or the startup reactorR_s may be configured to receive ammonia from multiple sources.

FIG. 7A schematically illustrates an example of a fast startup reactor,in accordance with one or more embodiments of the present disclosure.Such fast startup reactor may correspond to and/or comprise the startupreactor R_s shown in FIG. 6 . The fast startup reactor may comprise ahousing with electrical insulation and/or thermal insulation. Thehousing may comprise a cylindrical or tube shape. The housing maycomprise a cross-sectional shape. The cross-sectional shape may be acircle, an oval, an ellipse, or any polygon having three or more sides.The housing may comprise, for example, a ceramic material such as quartzor a metallic material such as aluminum or steel.

The housing may comprise an inner volume containing a catalyst bedand/or one or more electrodes (e.g., one or more copper electrodes). Theone or more electrodes may be in electrical communication with thecatalyst bed or a portion thereof. The housing may comprise an enclosedor partially enclosed volume that is configured to contain a gas (e.g.,ammonia) to enable processing of the gas. In cases where the gascomprises ammonia, such processing may comprise cracking or decomposingthe ammonia (or a portion of the ammonia). The fast startup reactor maycomprise a gas inlet configured to receive the ammonia. The fast startupreactor may further comprise a catalyst bed comprising one or morecatalysts. The one or more catalysts may comprise, for example, amodified metal foam catalyst. Additional types of catalyst materialsthat are compatible with the fast startup reactor may be used. Thecatalyst materials may be subjected to or may undergo one or moreenhancements and/or treatments (as shown and described in FIG. 9 ). Insome cases, the metal foam catalyst may comprise a nickel chromiumaluminum (NiCrAl) foam. The fast startup reactor may further comprise agas outlet configured to direct one or more gases (e.g., ammonia,nitrogen, and/or hydrogen) to another system or subsystem. In somecases, the gas outlet may be configured to direct hydrogen gas producedby the fast startup reactor to one or more fuel cells. In some cases,the gas outlet may be configured to direct hydrogen-nitrogen orhydrogen-nitrogen-ammonia mixture to the gas inlet of the main reactorR_m shown and described in FIG. 6 . In other cases, the gas outlet maybe configured to direct hydrogen gas produced by the fast startupreactor to one or more combustors to generate heat energy that can beused to power or heat the main reactor R_m shown and described in FIG. 6.

FIG. 7B schematically illustrates an example of a fast startup reactorcomprising one or more electrically conductive springs, in accordancewith one or more embodiments of the present disclosure. The one or moreelectrically conductive springs may be provided adjacent to the catalystbed. In some cases, the one or more electrically conductive springs maybe provided on opposite ends of the catalyst bed. The one or moreelectrically conductive springs may be in physical, electrical, and/orthermal communication with the catalyst bed and/or the one or moreelectrodes. The one or more electrically conductive springs may beconfigured to reduce thermal stresses on the foam catalyst when the foamcatalyst is subjected to thermal cycling. The one or more electricallyconductive springs may be configured to accommodate thermal expansionsduring heating of the catalyst and thermal contractions during coolingof the catalyst. The one or more electrically conductive springs mayserve to lighten and/or redistribute the mechanical load on the catalystbed so that the catalyst bed may withstand multiple thermal cycleswithout breaking or fracturing. In some cases, the one or more springsmay be configured to alleviate thermal stresses on the catalyst due to athermal expansion or a thermal contraction of the catalyst during one ormore thermal cycling procedures. The one or more springs may comprise,for example, copper or steel springs. The use of the one or moreelectrically conductive springs may allow the startup reactor to providefast startup capabilities with reduced or minimal thermal stresses onthe catalyst bed during rapid temperature changes.

FIG. 8 schematically illustrates a plot of gas temperature as a functionof time for a fast startup reactor comprising one or more electricallyconductive springs as shown in FIG. 7B. In some instances, the faststartup reactor comprising the one or more thermal springs may be usedto heat up the ammonia gas to 500° Celsius in less than 5 minutes. Insome instances, the fast startup reactor comprising the one or morethermal springs may be used to heat the ammonia gas to about 600°Celsius in less than 60 minutes. In some cases, when 112 watts ofheating power is provided to the catalyst, the ammonia gas may be heatedto 500° Celsius in less than 300 seconds. In some cases, when 157 wattsof heating power is provided to the catalyst, the ammonia gas may beheated to 500° Celsius in less than 200 seconds.

FIG. 9 schematically illustrates various types of enhancements and/ortreatments for metal foam catalyst materials that may be used for thefast startup reactor, in accordance with one or more embodiments of thepresent disclosure. Compatible metal foam catalysts may comprise anymetal alloy comprising nickel, chromium, iron, and/or aluminum, i.e.,Ni/Cr-X, Ni/Cr-X/Al-Y, and/or Ni/Fe-X/Cr-Y/Al-Z, where X, Y, and/or Zranges from 0 to 100. A surface of the metal foam catalysts may beprocessed (e.g., by etching, alloying, leaching, and/or using one ormore acidic treatments) to enhance a surface area of the catalystmaterial. The metal foam catalysts may also undergo a catalyst coatingoperation (e.g., by impregnation, PVD, or CVD) and/or one or more heattreatment operations (e.g., sintering, annealing, and/or calcining).Such processing of the metal foam catalyst material may produce acatalyst coated metal foam comprising one or more electrically resistivecatalysts.

FIG. 10 schematically illustrates startup time simulation data for thesystems and methods of the present disclosure. As used herein, startuptime may correspond to an amount of time needed to increase thetemperature of the reactor bed to a target temperature. The targettemperature may be at least about 100° Celsius, 200° Celsius, 300°Celsius, 400° Celsius, or more. For reactor systems comprising the faststartup reactors disclosed herein, the average reactor temperature maybe increased to the target temperature in less time than otherconventional reactor systems. For instance, when the heating power forthe presently disclosed systems is adjusted to at least about 150 wattsfor direct resistive heating of the catalyst bed, the reactor and/or thecatalyst bed may be heated to a target temperature of at least about 400degrees Celsius in under 30 seconds.

FIG. 11 schematically illustrates ammonia conversion efficiencysimulation data for the systems and methods of the present disclosure.As used herein, ammonia conversion efficiency may correspond to afraction of ammonia (by mass or moles) converted into one or moreconstituent components (e.g., hydrogen or nitrogen). For reactor systemscomprising the fast startup reactors disclosed herein, the ammoniaconversion efficiency may be greater than that of other conventionalreactor systems. For instance, when the heating power for the presentlydisclosed startup reactor is adjusted to at least about 250 watts fordirect resistive heating of the catalyst bed, the systems disclosedherein may achieve an ammonia conversion efficiency that is greater than90%, which indicates that more than 90% of the ammonia may be convertedinto one or more constituent components in less than a minute.

FIG. 12 schematically illustrates an example of a modular design for thestartup reactor, in accordance with one or more embodiments of thepresent disclosure. In some instances, the startup reactor may comprisea modular design that allows a plurality of layers comprising multiplereactor channels to be stacked on top of each other. Each of the layersmay comprise a metal foam catalyst and insulation (e.g., thermalinsulation and/or electrical insulation). In some cases, a separator maybe provided in between the one or more layers. In some cases, theseparator may be electrically insulated using electrical insulationcoatings such as boron nitride (BN) or other ceramic type materials. Theplurality of layers may be arranged such that the gas inlets and gasoutlets for each layer align on one side. Further, the plurality oflayers may be arranged such that the corresponding electrodes for eachlayer protrude in or out from the same side. The gas inlets and gasoutlets may be provided on a first side of each layer, and theelectrodes may be provided on a second side of each layer. The stackableand modular design shown in FIG. 12 may enhance scalability of thestartup reactor, and may enable direct heating of the metal foamcatalysts. The modular configuration may also reduce a distance betweenthe catalyst materials and one or more heat source for each layer. Insome embodiments, a metal housing with electrical insulation (e.g., aninsulation coating comprising boron nitride) may be used to improve theheating performance and ammonia conversion efficiency of the startupreactor.

FIG. 13 schematically illustrates transient time and transient reactortemperature data for the modular startup reactor design. The transienttime required to reach a target temperature may be greater than or equalto that of a single reactor unit due to the larger heat capacity of themodular startup reactor design, however, the modular startup reactordesigns may still reach a target temperature of about 500° Celsius inless than about 5 minutes. In some cases, when 112 watts of heatingpower is provided, the reactor may be heated to 500° Celsius in lessthan about 300 seconds. In some cases, when 157 watts of heating poweris provided, the reactor may be heated to 500° Celsius in less thanabout 200 seconds.

In one aspect, the present disclosure provides a system comprising afirst reactor module configured to receive a source material comprisingammonia. The first reactor module may comprise a first catalyst and astartup heating and reforming unit. The startup heating and reformingunit may comprise one or more electrodes for passing a current throughthe first catalyst to heat the first catalyst (e.g., by resistiveheating or Joule heating). The one or more electrodes may comprise, forexample, one or more copper electrodes. In some cases, the firstcatalyst may be used to generate hydrogen from the ammonia when thefirst catalyst is heated using the startup heating and reforming unit.

In some embodiments, the system may further comprise a second reactormodule in thermal and/or fluid communication with the first reactormodule. The second reactor module may comprise a second catalyst and oneor more main heating units for heating the second catalyst. In somecases, at least one of the one or more main heating units may beconfigured to heat at least a portion of the second catalyst based on acombustion of the hydrogen generated by the first reactor module. Insome cases, the second catalyst may be used to generate hydrogen fromammonia when the second catalyst is heated using the one or more mainheating units. In some embodiments, the one or more main heating unitsmay comprise, for example, an electrical heater and/or a combustionheater.

As described above, the system may comprise a first reactor module and asecond reactor module. The term “module,” as used herein, generallyrefers to a functional unit for performing one or more operations of aprocess (e.g., an ammonia cracking or decomposition process). A modulemay include one or more functional units. In some cases, a module maycomprise a reactor or a reformer. In some cases, the reactor or reformermay comprise a catalyst and/or one or more heating units for heating thecatalyst. In some cases, the reactor or reformer may include at leastone fluid input and/or at least one fluid output. The at least one fluidinput may be used to transport ammonia to the reactor or reformer. Theat least one fluid output may be used to transport hydrogen (or amixture of hydrogen and nitrogen, and optionally, trace ammonia) to oneor more fuel cells.

In some cases, at least one of the first catalyst and the secondcatalyst may comprise a metal foam catalyst. The metal foam catalyst maycomprise nickel, iron, chromium, and/or aluminum. In some cases, themetal foam catalyst may comprise one or more alloys comprising nickel,iron, chromium, and/or aluminum.

In some embodiments, the metal foam catalyst may comprise a catalyticcoating of one or more powder or pellet catalysts. The catalytic coatingmay comprise a metal material, a promoter material, and/or a supportmaterial. In some embodiments, the metal foam catalyst may be poroussuch that inner surfaces of the metal foam catalyst are covered by thecatalytic coating. The metal material may comprise, for example,ruthenium, nickel, rhodium, iridium, cobalt, iron, platinum, chromium,palladium, and/or copper. In some embodiments, the promoter material maycomprise at least one material selected from Li, Na, K, Rb, Cs, Mg, Ca,Ba, Sr, La, Ce, Pr, Sm, or Gd. In some embodiments, the support maycomprise at least one material selected from Al₂O₃, MgO, CeO₂, ZrO₂,La₂O₃, SiO₂, Y₂O₃, TiO₂, SiC, hexagonal BN (boron nitride), BNnanotubes, silicon carbide, one or more zeolites, LaAlO₃, CeAlO₃,MgAl₂O₄, CaAl₂O₄, or one or more carbon nanotubes.

In some embodiments, the catalytic coating may comprise one or moreruthenium-based precursors. The one or more ruthenium-based precursorsmay comprise, for example, RuCl₃ or Ru₃(CO)₁₂. In any of the embodimentsdescribed herein, the metal foam catalyst may have an apparentelectrical resistivity of at least about 8 micro ohm-meters (µΩm).

In some cases, the metal foam catalyst may be processed using one ormore etching, alloying, leaching, or acidic treatments to enhance asurface area of the metal foam catalyst. In some cases, the metal foamcatalyst may be heat treated (e.g., by sintering, calcining, and/orannealing). In some cases, the metal foam catalyst may be coated using aphysical vapor deposition treatment and/or a chemical vapor depositiontreatment. In some embodiments, the first reactor module may comprise aplurality of modular units that are stackable on top of each other. Eachof the plurality of modular units may comprise a metal foam catalyst andone or more reactor channels for directing ammonia to the metal foamcatalyst. The one or more reactor channels may comprise any suitabledesign or configuration that permits ammonia gas to be directed to asurface or internal volume of the metal foam catalyst. In some cases,the system may further comprise one or more insulated panels forseparating the plurality of modular units. The plurality of modularunits (and the metal foam catalysts with each of the modular units) maybe in thermal communication with one or more heat sources. In somecases, a first modular unit of the plurality of modular units may be inthermal communication with a first heat source, and a second modularunit of the plurality of modular units may be in thermal communicationwith a second heat source. The first heat source may be the same as thesecond heat source. Alternatively, the first heat source may bedifferent than the second heat source (e.g., the first heat source mayprovide heat energy by combustion, and the second heat source mayprovide heat energy by resistive heating or Joule heating). In somecases, a first modular unit and a second modular unit of the pluralityof modular units may be in thermal communication with the same heatsource. In other cases, the first modular unit and the second modularunit of the plurality of modular units may be in thermal communicationwith different heat sources.

In some embodiments, the plurality of modular units may be stackedtogether to scale the amount of hydrogen produced in parallel. In somecases, the plurality of modular units may be arranged such that edges ofthe modular units are flush with respect to each other. In other cases,the positions and/or orientations of the modular units may be adjustedrelative to each other to achieve a desired spatial configuration orprofile that fits within a target volume.

In some cases, the first reactor module may be in fluid communicationwith the second reactor module. Such fluid communication may permitammonia or other gases (e.g., hydrogen and/or nitrogen) to flow betweenthe first reactor module and the second reactor module. In some cases,the hydrogen generated using the first reactor module may be combustedto heat or partially heat the second reactor module or one or morecomponents of the second reactor module (e.g., the catalyst of thesecond reactor module). In some cases, the hydrogen generated using thefirst reactor module may be directed or diverted to one or more fuelcells to power the fuel cells. The fuel cells may use the hydrogengenerated using the first reactor module and/or the second reactormodule to generate electricity.

In some embodiments, the first reactor module may provide a startup timeof at most about 5 minutes to reach a target temperature of at leastabout 550° Celsius. In some embodiments, the first reactor module mayprovide a startup time of at most about 60 minutes to reach a targettemperature of at least about 550° Celsius. The first reactor module mayprovide an ammonia conversion efficiency of at least about 90%. In somecases, the first reactor module may have a power density of about 10watts of electrical power per cubic centimeter of reactor bed volume.

In some cases, at least one of the first reactor module and the secondreactor module may be configured for self-heat generation (i.e.,auto-thermal reforming) from electricity or hydrogen combustion. In someinstances, the first reactor module and/or the second reactor module maybe configured to combust the hydrogen respectively produced by the firstand second reactor modules to generate additional thermal energy. Suchadditional thermal energy may be used to heat the catalysts of the firstreactor module and/or the second reactor module.

In some embodiments, the system may further comprise one or more fuelcells in fluid communication with at least one of the first reactormodule and the second reactor module. The one or more fuel cells may beconfigured to receive hydrogen generated using the first reactor moduleand/or the second reactor module, and to use the hydrogen to produceelectrical energy.

In some cases, the system may further comprise a hybrid battery for loadfollowing and initial reactor heating power. The hybrid battery may beplaced in electrical communication with at least one of the firstreactor module and the second reactor module. In some cases, the hybridbattery may be used to pass a current through a catalyst of the firstreactor module and/or the second reactor module to enable resistiveheating or Joule heating. In some cases, the hybrid battery may beconfigured to adjust an amount of current provided to the first reactormodule and/or the second reactor module. In some cases, the hybridbattery may be configured to provide different currents to the firstreactor module and the second reactor module.

FIG. 64A schematically illustrates a system configuration for processingammonia during a startup operation, in accordance with one or moreembodiments of the present disclosure. In some cases, the ammoniareactor/reformer (6405) may be heated with an electricity input. In somecases, flow produced by the ammonia reactor/reformer (6405) may passthrough a heat exchanger (6404) to be supplied to one or more combustorsin the ammonia reactor/reformer (6405) as a combustion fuel. In somecases, flow produced by the ammonia reactor/reformer (6405) may passthrough a heat exchanger (6404) to be supplied at least in part back tothe ammonia reactor/reformer (6405). In some cases, an air cooled heatexchanger (6403) may be used to evaporate ammonia, before the ammonia issupplied to the heat exchanger (6404) and/or the ammoniareactor/reformer (6405). In some cases, one or more air supply units(6412) may supply air to the one or more combustors in the ammoniareactor/reformer (6405) for a combustion reaction.

FIG. 64B schematically illustrates a system configuration for processingammonia during a steady or post-startup operation, in accordance withone or more embodiments of the present disclosure. In some cases, flowproduced by the ammonia reactor/reformer (6405) may pass through a heatexchanger (6404) to be supplied at least in part to (i) one or moreadsorbents (6408 and 6409) and the fuel cell system (6410), and/or (ii)be supplied to one or more combustors in the ammonia reactor/reformer(6405). In some cases, flow produced by the ammonia reactor/reformer(6405) may pass through a heat exchanger (6404) to be supplied at leastin part back to the ammonia reactor/reformer (6405). In some cases,capturing the heat from the flow produced by the ammoniareactor/reformer (6405) back to the ammonia reactor/reformer (6405) mayimprove ammonia conversion efficiencies. In some cases, passing the flowproduced by the ammonia reactor/reformer (6405) through a heat exchanger(6404) may improve ammonia conversion efficiencies when the heatexchanger is used to heat input ammonia for the ammonia reactor/reformer(6405). In some cases, the flow produced by the ammonia reactor/reformer(6405) may pass through a heat exchanger (6404), one or more adsorbents(6408 and 6409) and a fuel cell system (6410) to be supplied to one ormore combustors in the ammonia reactor/reformer (6405) as a combustionfuel. In some cases, one or more air supply units (6412) supply air tothe one or more combustors in the ammonia reactor/reformer (6405) for acombustion reaction. In some cases, the flow produced by the ammoniareactor/reformer (6405) may pass through a heat exchanger (6404), andthe flow may then be supplied to the one or more combustors in theammonia reactor/reformer (6405) as a combustion fuel. In some cases, thefuel cell system (6410) may consume hydrogen and generate usefulelectricity. In some cases, at least part of the ammoniareactor/reformer (6405) may be heated with an electricity input. In somecases, the ammonia reactor/reformer (6405) may not be heatedelectrically. In some cases, the one or more adsorbents may comprise atemperature sensor attached thereto, which may indicate and/or monitorthe quality or the capacity of the adsorbent over time. Shown is apressure sensor (P); a temperature sensor (T); an ammonia sensor (A); aliquid fuel storage tank (6401); a liquid fuel supply unit (6402) (e.g.,valve, pump, mass flow controllers, etc.); an optional air-cooled/heatedheat exchanger (6403) (this heat exchanger may be coupled to the fuelcell heat dissipation unit and/or ambient to evaporate liquid fuel); aheat exchanger (6404) (e.g., gas to gas, liquid to gas, liquid/gas twophase flow to gas heat exchangers); an ammonia reactor/reformer (6405);an optional mass flow controller or mass flow meter (6406); a flowregulator unit (6407) (e.g., 3-way valve, valve, back pressureregulator, etc.); an adsorbent (6408); an optional adsorbent (6409); afuel cell system (6410); a gas supply unit (6411) (e.g., valve, massflow controllers, check valve, etc.); and an air supply unit (6412)(e.g., fan, blower, compressor, etc.).

In some cases, the system may further comprise a selective catalyticreduction (SCR) system (e.g., SCR catalyst) to remove nitrous oxides(NO_(x)) from one or more combustion exhaust streams. In some cases, theSCR system may receive ammonia (e.g., to use as a reducing agent toreduce NO_(x)) from the one or more ammonia tanks. In some cases, theSCR system may receive urea from one or more urea tanks. In some cases,the SCR system may receive a mixture of urea and water from one or moreurea and water mixture tanks. In some cases, the SCR system may receiveurea and water from one or more urea tanks and one or more water tanks.

FIG. 65 schematically illustrates a system configuration for processingammonia during a startup operation, in accordance with one or moreembodiments of the present disclosure. In some cases, the ammoniareactor/reformer (6505) is heated with an electricity input. In somecases, flow produced by the ammonia reactor/reformer (6505) may passthrough a heat exchanger (6504) and at least one adsorbent (6507) to besupplied to one or more combustors in the ammonia reactor/reformer(6505) as a combustion fuel. In some cases, flow produced by the ammoniareactor/reformer (6505) may pass through a heat exchanger (6504) to besupplied at least part back to the ammonia reactor/reformer (6505). Insome cases, air cooled heat exchanger (6503) may be used to evaporateammonia before the ammonia is supplied to the heat exchanger (6504)and/or ammonia reactor/reformer (6505). In some cases, one or more airsupply units (6512) may supply air to the one or more combustors in theammonia reactor/reformer (6505) for a combustion reaction. Shown is apressure sensor (P); a temperature sensor (T); an ammonia sensor (A); aliquid fuel storage tank (6501); a liquid fuel supply unit (6502) (e.g.,valve, pump, mass flow controllers, etc.); an optional air-cooled/heatedheat exchanger (6503) (e.g., coupled to the fuel cell heat dissipationunit and/or ambient to evaporate liquid fuel); a heat exchanger (6504)(e.g., gas to gas, liquid to gas, liquid/gas two phase flow to gas heatexchangers); ammonia reactor/reformer (6505); an optional mass flowcontroller or mass flow meter (6506); an adsorbent (6507); a flowregulator unit (6508) (e.g., 3-way valve, valve, back pressureregulator, etc.); an optional adsorbent (6509); a fuel cell system(6510); a gas supply unit (6511) (e.g., valve, mass flow controllers,check valve, etc.); and an air supply unit (6512) (e.g., fan, blower,compressor, etc.).

FIG. 66 schematically illustrates a system configuration for processingammonia during a steady or post-startup operation, in accordance withone or more embodiments of the present disclosure. In some cases, flowproduced by the ammonia reactor/reformer (6605) may pass through a heatexchanger (6604) to be supplied at least in part to (i) one or moreadsorbents (6607 and 6609), and then (ii) the fuel cell system (6610)and/or the one or more combustors in the ammonia reactor/reformer(6605). In some cases, flow produced by the ammonia reactor/reformer(6605) may pass through a heat exchanger (6604) to be supplied at leastin part back to the ammonia reactor/reformer (6605). In some cases,capturing the heat from the flow produced by the ammoniareactor/reformer (6605) back to the ammonia reactor/reformer (6605) mayimprove ammonia conversion efficiencies. In some cases, passing the flowproduced by the ammonia reactor/reformer (6605) through a heat exchanger(6604) may improve ammonia conversion efficiencies when the heatexchanger is used to heat input ammonia for the ammonia reactor/reformer(6605). In some cases, the flow produced by the ammonia reactor/reformer(6605) may be supplied to one or more combustors in the ammoniareactor/reformer (6605) as a combustion fuel. In some cases, the flowproduced by the ammonia reactor/reformer (6605) may pass through a heatexchanger (6604), one or more adsorbents (6607 and 6609), and the fuelcell system (6610) to be supplied to one or more combustors in theammonia reactor/reformer (6605) as a combustion fuel. In some cases, oneor more air supply units (6612) may supply air to the one or morecombustors in the ammonia reactor/reformer (6605) for a combustionreaction. In some cases, the fuel cell system (6610) may consumehydrogen and generate useful electricity. In some cases, at least partof the ammonia reactor/reformer (6605) may be heated with an electricityinput. In some cases, the ammonia reactor/reformer (6605) may not beheated electrically. Shown is a pressure sensor (P); a temperaturesensor (T); an ammonia sensor (A); a liquid fuel storage tank (6601); aliquid fuel supply unit (6602) (e.g., valve, pump, mass flowcontrollers, etc.); an optional air-cooled/heated heat exchanger (6603)(e.g., coupled to the fuel cell heat dissipation unit and/or ambient toevaporate liquid fuel); a heat exchanger (6604) (e.g., gas to gas,liquid to gas, liquid/gas two phase flow to gas heat exchangers);ammonia reactor/reformer (6605); an optional mass flow controller ormass flow meter (6606); an adsorbent (6607); a flow regulator unit(6608) (e.g., 3-way valve, valve, back pressure regulator, etc.); anoptional adsorbent (6609); a fuel cell system (6610); a gas supply unit(6611) (e.g., valve, mass flow controllers, check valve, etc.); and anair supply unit (6612) (e.g., fan, blower, compressor, etc.).

FIG. 67 schematically illustrates an example of a system reactor and/orhotbox configuration, in accordance with one or more embodiments of thepresent disclosure. One or more combustion reactors and one or moreelectrical reactors may be configured for ammonia reforming. In somecases, an ammonia stream (6701) may pass through a conduit that isconcentric to the combustion reactor such that the ammonia stream (6701)is pre-heated by heat from the combustion reactor. In the configurationshown in FIG. 67 , the ammonia stream (6701) may flow in parallel (e.g.,along the same direction) to the reactants and products of thecombustion reaction, and heat may transfer across the walls of theconduit (from the reactants and products of the combustion reaction) tothe ammonia stream (6701). In some cases, preheated ammonia (6702) mayenter the electrical reactor for ammonia reforming. In some cases, anexit stream (6703) (e.g., comprising 50% or more H₂/N₂ and 50% or lessNH₃ by molar fraction) may then exit from the electrical reactor andenter the combustion reactor for further ammonia reforming. In somecases, an exit stream (6704) (e.g., comprising 98% or more H₂/N₂ and 2%or less NH₃ by molar fraction) may exit the combustion reactor, andenter a heat exchanger to heat the ammonia stream (6701) being input tothe combustion reactor and the electrical reactor. In some cases, theexit stream (6703) from the electrical reactor may enter the combustionreactor in proximity to a region of the combustion reactor such that theexit stream (6703) is further reformed in the combustion reactoradjacent to the region. In some cases, the region of the combustionreactor may comprise a relatively low thermal gradient between theammonia and the combustion gases (compared to another region of thecombustion reactor). In some cases, the region of the combustion reactormay comprise relatively low amount of combustion gases for combusting togenerate heat, compared to another region of the combustion reactor.Shown is an electrical reactor (“E-reactor”); at least partiallyembedded electrical heater (E_1) in the electrical reactor; a combustionreactor (“C-reactor”); at least partially embedded combustion heater(C_1) in the combustion reactor; ammonia preheating through combustor in6701; preheated ammonia combustor out / E-reactor in (6702); E-reactorout / C-reactor in (6703); C-reactor out (6704); combustion fuelcomprising hydrogen (6705); air in (6706); and combustion exhaust(6707); one or more catalysts in the electrical reactor; and one or morecatalysts in the combustion reactor. The one or more catalysts in theelectrical reactor may be the same or different as the one or morecatalysts in the combustion reactor. Locations of the inlet ports andthe outlet ports of the reactors in the flow diagram may be changed forvarious designs. In some cases, both the inlet ports and the outletports may be positioned at similar locations on the reactor or oppositelocations on the reactor along the length.

FIG. 68 schematically illustrates an example of a system reactor and/orhotbox configuration, in accordance with one or more embodiments of thepresent disclosure. In some cases, one or more combustion reactors andone or more electrical reactors may be configured for ammonia reforming.In some cases, an ammonia stream (6801) may pass through a conduit thatis concentric to the combustion reactor such that the ammonia stream(6801) is pre-heated using thermal energy from the combustion reactor.In the configuration shown in FIG. 68 , the ammonia stream (6801) mayflow counter (e.g., in an opposite direction) to the reactants andproducts of the combustion reaction, and heat may transfer across thewalls of the conduit (from the reactants and products of the combustionreaction) to the ammonia stream (6801). In some cases, preheated ammonia(6802) may enter the electrical reactor for ammonia reforming. In somecases, an exit stream (6803) (e.g., comprising 50% or more H₂/N₂ and 50%or less NH₃ by molar fraction) may then exit from the electrical reactorand enter the combustion reactor for further ammonia reforming. In somecases, an exit stream (6804) may then exit the combustion reactor (e.g.,comprising 98% or more H₂/N₂ and 2% or less NH₃ by molar fraction) andenter a heat exchanger to heat up the ammonia stream (6801) being inputto the combustion reactor and the electrical reactor. In some cases,ammonia may be heated by a combustion reactor and an electrical reactorin sequence, and then flowed through a heat exchanger to heat up theammonia stream (6801) being input to the combustion reactor and theelectrical reactor. In some cases, the exit stream (6803) from theelectrical reactor may be flowed through in proximity to a region of thecombustion reactor to further reform in the combustion reactor. In somecases, ammonia output from the electrical reactor may be flowed throughan entry portion (near 6803) of the combustion reactor and exit at apoint that is distant from the entry portion (near 6804). Shown is anelectrical reactor (“E-reactor”); at least partially embedded electricalheater (E_1) in the electrical reactor; a combustion reactor(“C-reactor”, C_1); at least partially embedded combustion heater (C_1)in the combustion reactor; ammonia preheating through combustor in(6801); preheated ammonia through combustor out / E-reactor in (6802);E-reactor out / C-reactor in (6803); C-reactor out (6804); combustionfuel comprising hydrogen (6805); air in (6806); combustion exhaust(6807); one or more catalysts in the electrical reactor; and one or morecatalysts in the combustion reactor. The one or more catalysts in theelectrical reactor may be the same or different as the one or morecatalysts in the combustion reactor. Locations of the inlet and theoutlet ports of the reactors in the flow diagram may be changed forvarious designs. In some cases, both the inlet ports and the outletports may be positioned at similar locations on the reactor or oppositelocations on the reactor along the length.

FIG. 69 schematically illustrates an example of a system reactor and/orhotbox configuration, in accordance with one or more embodiments of thepresent disclosure. One or more combustion reactors and one or moreelectrical reactors may be configured for ammonia reforming. In somecases, an ammonia stream (6901) may pass through a conduit that isconcentric to the combustion reactor such that the ammonia stream (6901)is pre-heated using thermal energy from the combustion reactor. In theconfiguration shown in FIG. 69 , the ammonia stream (6901) may flowcounter (e.g., in an opposite direction) to the reactants and productsof the combustion reaction, and heat may transfer across the walls ofthe conduit (from the reactants and products of the combustion reaction)to the ammonia stream (6901). In some cases, preheated ammonia (6902)enters the combustion reactor for ammonia reforming. In some cases, anexit stream (6903) (e.g., comprising 50% or more H₂/N₂ and 50% or lessNH₃ by molar fraction) may then exit from the combustion reactor andenter the electrical reactor for further ammonia reforming. In somecases, an exit stream (6904) may then exit the electrical reactor (e.g.,comprising 98% or more H₂/N₂ and 2% or less NH₃ by molar fraction) andenter a heat exchanger to heat up the ammonia stream (6901) being inputto the combustion reactor and the electrical reactor. In some cases,ammonia output from the combustion reactor may be recycled (6902) to aportion of the combustion reactor that is relatively cold compared toanother portion of the combustion reactor to heat up the relatively coldportion. In some cases, the relatively cold portion may be in proximityto where the ammonia makes first contact with combustion gases of thecombustion reactor. In some cases, the ammonia output from thecombustion reactor after recycling through the combustion reactor (6903)may be further heated by the electrical reactor before being input to aheat exchanger. Shown is an electrical reactor (“E-reactor”); at leastpartially embedded electrical heater (E_1) in the electrical reactor; acombustion reactor (“C-reactor”); at least partially embedded combustionheater (C_1) in the combustion reactor; ammonia preheating throughcombustor in (6901); ammonia preheating through combustor out /C-reactor in (6902); C-reactor out / E-reactor in (6903); E-reactor out(6904); combustion fuel comprising hydrogen (6905); air in (6906);combustion exhaust (6907); one or more catalyst in the electricalreactor; and one or more catalyst in the combustion reactor. One or morecatalyst in the electrical reactor may be the same or different with theone or more catalyst in the combustion reactor. Locations of the inletports and the outlet ports of the reactors in the flow diagram may bechanged for various designs. In some cases, both the inlet ports and theoutlet ports may be positioned at similar locations on the reactor oropposite locations on the reactor along the length.

FIG. 70 schematically illustrates an example of a system reactor and/orhotbox configuration during a startup operation, in accordance with oneor more embodiments of the present disclosure. In some cases, the outputstream comprising hydrogen and/or nitrogen from the combustor reactor,electrical reactor, or both may be flowed through a heat exchanger to beused as a combustion fuel in the combustor reactor. Shown is liquid,liquid/gas two phase, or gaseous ammonia (7001); ammonia gas (7002);product gas comprising hydrogen, nitrogen, and ammonia (7003); cooledproduct gas (7004); combustion fuel gas comprising hydrogen and nitrogen(7005); air (7006); combustion exhaust (7007); and electricity intoC-/E-reactor module (7008).

FIG. 71 schematically illustrates an example of a system reactor and/orhotbox configuration during startup, in accordance with one or moreembodiments of the present disclosure. In some cases, the output streamcomprising hydrogen and/or nitrogen from the combustor reactor,electrical reactor, or both may be flowed through a heat exchanger andthen an adsorbent to be used as a combustion fuel in the combustorreactor. In the example shown in FIG. 71 , the adsorbent may removetrace amounts of ammonia (e.g., 10,000 ppm by volume) from the outputstream (7104) to improve combustion characteristics of the filteredstream (7105) input into the C-/E- reactor module (7108). Shown isliquid, liquid/gas two phase, or gaseous ammonia (7101); ammonia gas(7102); product gas comprising hydrogen, nitrogen, and ammonia (7103);cooled product gas (7104); filtered combustion fuel gas comprisinghydrogen and nitrogen (7105); air (7106); combustion exhaust (7107);electricity into C-/E- reactor module (7108).

FIG. 72 schematically illustrates an example of a system reactor and/orhotbox configuration during a steady or post-startup operation, inaccordance with one or more embodiments of the present disclosure. Insome cases, the output stream (7203) comprising hydrogen and nitrogenfrom the combustor reactor, electrical reactor, or both may be flowedthrough a heat exchanger and then an adsorbent. The output stream (7206)(comprising hydrogen that is not used by the fuel cell, and/or nitrogen)of a fuel cell may be used as a combustion fuel for the combustorreactor. In some cases, the output stream (7206) of a fuel cell maycomprise about 10 to 40 % the hydrogen from the output stream (7203)from the combustor reactor, electrical reactor, or both. In some cases,the output stream (7206) of a fuel cell may comprise about 5 to 50 % ofthe hydrogen from the output stream (7203) from the combustor reactor,electrical reactor, or both. In some cases, the output stream (7206) ofa fuel cell may comprise about 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90,or 100 % of the hydrogen from the output stream (7203) from thecombustor reactor, electrical reactor, or both. Shown is liquid,liquid/gas two phase, or gaseous ammonia (7201); ammonia gas (7202);product gas comprising hydrogen, nitrogen, and ammonia (7203); cooledproduct gas (7204); filtered product gas (7205); combustion fuel gascomprising unconverted hydrogen from fuel cell and nitrogen (7206); air(7207); combustion exhaust (7208); optional electricity into C-/E-reactor module (7209); and electricity output from fuel cell (7210).

FIG. 73 schematically illustrates an example of a system reactor and/orhotbox configuration during a steady or post-startup operation, inaccordance with one or more embodiments of the present disclosure. Insome cases, the output stream (7303) comprising hydrogen and nitrogenfrom the combustor reactor, electrical reactor, or both may be flowedthrough a heat exchanger and then an adsorbent and then a hydrogenseparation unit (e.g., pressure swing adsorption [PSA] system or amembrane separation system). In some cases, product flow (7306) from thehydrogen separation unit comprising purified hydrogen may be input to afuel cell. In some cases, an exit flow or discharge stream (7307) fromthe hydrogen separation unit comprising hydrogen and nitrogen may beused as a combustion fuel for the combustor reactor. In some cases, anexit flow or discharge stream (7307) of a hydrogen separation unit maycomprise about 10 to 40 % of the hydrogen from the output stream (7303)from the combustor reactor, electrical reactor, or both. In some cases,an exit flow or discharge stream (7307) of a hydrogen separation unitmay comprise about 5 to 50 % of the hydrogen from the output stream(7303) from the combustor reactor, electrical reactor, or both. In somecases, an exit flow or discharge stream (7307) of a hydrogen separationunit may comprise about 0, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, or100 % of the hydrogen from the output stream (7303) from the combustorreactor, electrical reactor, or both. Shown is liquid, liquid/gas twophase, or gaseous ammonia (7301); ammonia gas (7302); product gascomprising hydrogen, nitrogen, and ammonia (7303); cooled product gas(7304); filtered product gas (7305); filtered product gas comprisingmostly hydrogen (7306); hydrogen separation unit discharge streamcomprising hydrogen and nitrogen (7307); air (7308); combustion exhaust(7309); optional electricity into combustor/electrical reactor module(7310); and electricity output from fuel cell (7311).

FIG. 83 shows a flow diagram for a startup method, in accordance withone or more embodiments of the present disclosure. In some cases, thestartup method may comprise (1) heating an electrical reactor to anelectrical reactor target temperature; (2) inputting ammonia into theelectrical reactor and reforming ammonia with the electrical reactor;(3) combusting at least a portion of an electrical reactor exit flowwith air to heat a combustor reactor; (4) optionally, turning off theelectrical reactor; and/or (5) increasing an ammonia flow rate to atleast a predefined flow rate. In some cases, process (1) and (2) may beperformed in sequence or in parallel. In some cases, at least twoprocesses in processes (1)-(5) may be performed in sequence or inparallel. Once condition (5) is reached, and self-sustained auto-thermalreforming is maintained (i.e., a steady-state condition), the ammoniaflow rate may be further increased above a predefined rate depending onoperating requirements (e.g., fuel cell output power, reactortemperature(s), combustor temperature(s), reactor pressure(s), ammoniaflowrate, etc.) while maintaining auto-thermal reforming. Process (4)may be executed or un-executed depending on combustor reactortemperature and ammonia conversion efficiency. Electrical reactor may beused to balance temperature distribution. In some cases, if the fuelcell efficiency is high, electricity may be used as a main source ofheating power as well.

FIG. 84 shows a flow diagram for a startup method, in accordance withone or more embodiments of the present disclosure. In some cases, thestartup method may comprise (1) heating an electrical reactor to atleast an electrical reactor target temperature; (2) inputting ammoniawith at least an initial target flow rate to the electrical reactor; (3)inputting (i) air, and (ii) at least a fraction of an exit flow from theelectrical reactor to a combustor reactor; (4) igniting, at thecombustor reactor and adjusting the flow rate of air into the combustorreactor; (5) heating the combustor reactor to at least a first targetcombustor reactor temperature; (6) turning off the electrical reactor;(7) using a controller, increasing the ammonia flow rate incrementallyto at least a second target flow rate and simultaneously controlling andincreasing the combustor reactor air flow rate to maintain at least asecond target combustor reactor temperature. In some cases, the secondtarget combustor reactor temperature may be the same or different as thefirst target combustor reactor temperature; (8) inputting at least aportion of an exit flow from the combustor reactor to a fuel cell; (9)reacting the exit flow from the combustor reactor in the fuel cell togenerate electrical power; (10) inputting at least a portion of an exitflow from the fuel cell to the combustor reactor; (11) adjusting thecombustor reactor air flow rate to maintain at least a third targetcombustor reactor temperature. In some cases, the third target combustorreactor temperature may be the same or different as the first targetcombustor reactor temperature or the second target combustor reactortemperature; (12) adjusting the ammonia flow rate to at least a thirdtarget flow rate (e.g., by fine-tuning or decreasing/increasing theammonia flow rate), and/or adjusting the combustor reactor air flow rateto maintain at least a fourth target combustor reactor temperature. Insome cases, the fourth target combustor reactor temperature may be thesame or different as the first target combustor reactor temperature, thesecond target combustor reactor temperature, or the third targetcombustor reactor temperature; and/or (13) achieving a predeterminedinitial operational condition (i.e., a steady-state condition). In somecases, at least two processes in processes (1)-(13) may be performed insequence or in parallel. In some cases, the startup process may beperformed without process (1), (2), (3), (4), (5), (6), (7), (8), (9),(10), (11), (12), or a combination thereof. Combustor reactor outflowmay pass through adsorbents and heat exchanger to remove unconvertedammonia, and cool down and/or recuperate heat before entering the fuelcells. Process (6) may be executed anywhere in the flow chart as long asthe combustor reactor temperature is above predetermined thresholdtemperature. Process (6) may be unexecuted if the combustor reactortemperature falls below predetermined threshold temperature. Process (9)may be executed anywhere after process (8).

FIG. 85 shows a flow diagram for a startup method, in accordance withone or more embodiments of the present disclosure. In some cases, astartup method may comprise (1) heating an electrical reactor to atleast an electrical reactor target temperature; (2) inputting ammoniawith at least an initial target flow rate into the electrical reactor;(3) inputting an exit flow from the electrical reactor to a fuel cell;(4) inputting (i) air and (ii) an exit flow from the fuel cell to acombustor reactor, and igniting the exit flow and the air in thecombustor reactor; (5) reacting the hydrogen in the exit flow from theelectrical reactor and/or the combustor reactor to generate power fromthe fuel cell; (6) heating the combustor reactor to at least a firstcombustor reactor target temperature; (7) turning off the electricalreactor; (8) using a controller, increasing the ammonia flow rateincrementally to at least a second target flow rate and simultaneouslycontrolling (e.g., increasing) the flow rate of the air to maintain atleast a second target combustor reactor temperature. In some cases, thesecond target combustor reactor temperature may be the same or differentas the first target combustor reactor temperature; (9) adjusting theflow rate of air to maintain at least a third target combustor reactortemperature. In some cases, the third target combustor reactortemperature may be the same or different as the first target combustorreactor temperature or the second target combustor reactor temperature;(10) adjusting the flow rate of ammonia to at least a second target flowrate (e.g., by fine-tuning or decreasing/increasing the ammonia flowrate), and adjusting the flow rate of air to the combustor reactor tomaintain at least a fourth combustor reactor temperature. In some cases,the fourth target combustor reactor temperature may be the same ordifferent as the first target combustor reactor temperature, the secondtarget combustor reactor temperature, or the third target combustorreactor temperature; and/or (13) achieving a predetermined initialoperational condition. In some cases, at least two processes inprocesses (1)-(13) may be performed in sequence or in parallel. In somecases, the startup process may be performed without process (1), (2),(3), (4), (5), (6), (7), (8), (9), (10), (11), (12), or a combinationthereof. Reactor exit flow may pass through adsorbents and heatexchanger to remove unconverted ammonia, and cool down and/or recuperateheat before entering the fuel cells. Process (7) may be executedanywhere in the flow chart as long as the C-reactor temperature is abovepredetermined threshold temperature. Process (7) may be unexecuted ifthe C-reactor temperature falls below predetermined thresholdtemperature. Process (5) may be executed anywhere after process (3).

FIG. 86 shows a flow diagram for a startup method, in accordance withone or more embodiments of the present disclosure. In some cases, astartup method may comprise (1) heating an electrical reactor to anelectrical reactor target temperature; (2) inputting ammonia with atleast an initial target flow rate to the electrical reactor; (3)inputting at least a fraction of an exit flow from the electricalreactor to a combustor reactor; (4) inputting air into the combustorreactor using an air supply unit, and igniting the exit flow from theelectrical reactor and the air in the combustor reactor; (5) heating thecombustor reactor to a first target combustor reactor temperature; (6)using a controller, increasing the ammonia flow rate incrementally to atleast a second target flow rate and simultaneously controlling (e.g.,increasing) the flow rate of air into the combustor reactor to maintainat least a second target combustor reactor temperature. In some cases,the second target combustor reactor temperature may be the same ordifferent from the first target combustor reactor temperature; and (7)achieving a predetermined initial operational condition. In some cases,at least two processes in processes (1)-(6) may be performed in sequenceor in parallel. In some cases, the startup process may be performedwithout process (1), (2), (3), (4), (5), (6), or a combination thereof.Reactor exit flow may pass through adsorbents and heat exchanger toremove unconverted ammonia, and cool down and/or recuperate heat beforeentering the fuel cells. E-reactor may be turned off if the C-reactortemperature is above predetermined threshold temperature.

It is noted herein that any of the steps or processes described withrespect to FIGS. 83-86 may be combined with the others of the steps orprocesses described with respect to FIGS. 83-86 , and that the examplesdescribed with respect to FIGS. 83-86 should not be construed aslimiting the disclosure.

FIG. 87 shows a flow diagram for a post-startup operation method, inaccordance with one or more embodiments of the present disclosure. For aset of given system operational parameters, self-sustaining auto-thermaloperational conditions may be predetermined (e.g., min./max. NH₃ flowrates, corresponding FC power and hydrogen consumption rates, batterymin./max. states of charge [SOC], min./max. air flow rates, etc.). Insome aspects, the present disclosure provides a method for maintainingand/or adjusting operational parameters of a system comprising a fuelcell to maintain and/or adjust power output for the fuel cell. In somecases, the method may comprise monitoring the power output for the fuelcell, and automatically adjusting (increasing or decreasing) the poweroutput (e.g., by monitoring the electrical load coupled to the fuelcell). In some cases, the method may adjust various operationalparameters (8703), including, but not limited to: air flow rate for thecombustor reactor, ammonia flow rate into the system or any componentthereof (e.g., combustor reactor, electrical heater, etc.), and/or fuelcell hydrogen utilization. “*” indicates adjustable conditions includecombustor air flow rate, ammonia (NH₃) flow rate, fuel cell (FC) H₂utilization, or E-reactor power. “a” indicates predetermined achievablefuel cell (FC) hydrogen utilization or consumption rate from the FCinlet flow to maintain self-sustaining auto-thermal reforming for agiven FC inlet flow rate. “b” indicates predetermined maximum NH₃ flowrate. “c” indicates predetermined minimum NH₃ flow rate. Incremental ordecremental change in NH₃ flow rate may be based on predetermined valueand/or percentage of current value. In some cases, a controller maycontrol NH₃ flow rate, control air flow rate, control flow pressures,control valves, control FC power output, control battery power output,control E-reactor power input, or any combination thereof. In somecases, a sensor may measure temperatures, pressures, fuel cell poweroutput, battery power outputs, battery SOC, fuel cell hydrogenconsumption, and NH₃ conversion efficiency.

In some cases, the method may comprise increasing the power output ofthe fuel cell (8701). In some cases, the method may comprise comparinghydrogen utilization rate of the fuel cell to a predetermined thresholdvalue. In some cases, the method may comprise increasing the poweroutput of the fuel cell by increasing the hydrogen utilization and/orconsumption (while still keeping the hydrogen utilization at a levellower than the predetermined threshold value) when the hydrogenutilization rate of the fuel cell is lower than the predeterminedthreshold value. In some cases, the method may comprise comparing theammonia flow rate into the system to a predetermined ammonia flow ratevalue when the hydrogen utilization rate of the fuel cell is equal to orabove the predetermined threshold value. In some cases, thepredetermined ammonia flow rate value may be a maximum ammonia flow ratevalue for the system. In some cases, the method may comprise increasingthe ammonia flow rate when the ammonia flow rate into the system is lessthan the predetermined ammonia flow rate value. In some cases, themethod may comprise maintaining the ammonia flow rate when the ammoniaflow rate into the system is greater than the predetermined ammonia flowrate value. In some cases, the method may comprise increasing the poweroutput of the fuel cell when the ammonia flow rate into the system isgreater than the predetermined ammonia flow rate value.

In some cases, the method may comprise decreasing the power output ofthe fuel cell (8702). In some cases, the method may comprise comparingthe ammonia flow rate into the system to a predetermined ammonia flowrate value. In some cases, the predetermined ammonia flow rate value maybe a minimum ammonia flow rate value for the system. In some cases, themethod may comprise reducing the ammonia flow rate when the ammonia flowrate into the system is above the predetermined ammonia flow rate value.In some cases, the method may comprise maintaining the ammonia flow ratewhen the ammonia flow rate into the system falls below or at thepredetermined ammonia flow rate value. In some cases, the method maycomprise decreasing the power output of the fuel cell when the ammoniaflow rate into the system falls below the predetermined ammonia flowrate value.

In some cases, the method may comprise a shutdown process. In somecases, the shutdown process may comprise reducing any one of or acombination of ammonia flow rate, air flow rate, and fuel cell power tozero.

In some cases, the method may comprise a fault detection system. In somecases, the fault detection system may detect a fault. In some cases, afault may be categorized as a major fault or a minor fault. An exampleof a maj or fault may include a fracture of a reactor vessel or aleakage of ammonia above predetermined leakage levels. An example of aminor fault may include the temperature of a reactor or a heater beingoffset (e.g., by 10% or more) from a target temperature, or an increasein ammonia concentration in the one or more inlet streams to the one ormore adsorbents or the fuel cell system above predetermined thresholdconcentrations. In some cases, when a major fault is detected by thefault detection system, a shutdown process may be initiated. In somecases, when a minor fault is detected by the fault detection system, areactor in the system may operate in a standby mode while maintaining apredetermined temperature. In some cases, when a minor fault is detectedby the fault detection system, a fuel cell in the system may beshutdown. In some cases, in the event that the fuel cell power needs tobe turned off intermittently, the event may be classified as a minorfault. In some cases, a hot standby mode (e.g., without the fuel celloutputting power) may be maintained until the shut down process isexecuted. In some cases, the hot standby mode (e.g., without the fuelcell outputting power) may be maintained until fuel cell power output isexecuted.

FIG. 88 shows a process flow diagram for a post-startup operationprocess, in accordance with one or more embodiments of the presentdisclosure. Based on a set of given system operational parameters,self-sustaining auto-thermal operational conditions may be predetermined(e.g., min./max. NH₃ flow rates, corresponding FC power and hydrogenconsumption rates, battery min./max. SOCs, min./max. air flow rates,etc.). In some aspects, the present disclosure provides a method formaintaining and/or adjusting operational parameters of a systemcomprising a fuel cell to maintain and/or adjust power output for thefuel cell. In some cases, the method may comprise determining whetherthe power output for the fuel cell is greater or lower than anelectrical energy or power demand. In some cases, the method may adjustvarious operational parameters (8803), including, but not limited to:air flow rate for the combustor reactor, ammonia flow rate into thesystem or any component thereof (e.g., combustor reactor, electricalheater, etc.), and/or fuel cell hydrogen utilization. “*” indicatesadjustable conditions include combustor air flow rate, NH₃ flow rate,fuel cell (FC) H₂ utilization, or E-reactor power. “a” indicatespredetermined achievable Fuel Cell hydrogen utilization or consumptionrate from the FC inlet flow to maintain self-sustaining auto-thermalreforming for a given FC inlet flow rate. “b” indicates predeterminedMaximum NH₃ flow rate. “c” indicates predetermined Minimum NH₃ flowrate. “d” indicates predetermined Maximum battery state of charge. “e”indicates predetermined Minimum battery state of charge. Incremental ordecremental change in NH₃ flow rate is based on predetermined valueand/or percentage of current value. In some cases, a controller maycontrol NH₃ flow rate, control air flow rate, control flow pressures,control valves, control FC power output, control battery power output,control E-reactor power input, or any combination thereof. In somecases, a sensor may measure temperatures, pressures, fuel cell poweroutput, battery power outputs, battery SOC, fuel cell hydrogenconsumption, and NH₃ conversion efficiency.

In some cases, the method may comprise increasing the power output ofthe fuel cell (8801). In some cases, the method may comprise comparinghydrogen utilization rate of the fuel cell compared to a predeterminedthreshold value. In some cases, the method may comprise increasing thepower output of the fuel cell by increasing the hydrogen utilizationand/or consumption (while still keeping the hydrogen utilization at alevel lower than the predetermined threshold value). In some cases, themethod may comprise using a battery to supplement the power output fromthe fuel cell to meet the electrical energy or power demand. In somecases, the method may comprise comparing the ammonia flow rate into thesystem to a predetermined ammonia flow rate value. In some cases, thepredetermined ammonia flow rate value may be a maximum ammonia flow ratevalue for the system. In some cases, the method may comprise increasingthe ammonia flow rate. In some cases, the method may comprisemaintaining the ammonia flow rate. In some cases, the method maycomprise increasing the power output of the fuel cell. In some cases,the method may comprise limiting an electrical load associated with theelectrical energy or power demand.

In some cases, the method may comprise decreasing the power output ofthe fuel cell (8802). In some cases, the method may comprise determiningif a battery has a state of charge (SOC) that is above a predeterminedthreshold value. In some cases, the method comprises comparing theammonia flow rate into the system to a predetermined ammonia flow ratevalue. In some cases, the predetermined ammonia flow rate value may be aminimum ammonia flow rate value for the system. In some cases, themethod may comprise reducing the ammonia flow rate. In some cases, themethod may comprise maintaining the ammonia flow rate. In some cases,the method may comprise charging the battery using electrical energy orpower generated by the fuel cell. In some cases, the method may comprisedetermining if the battery is fully charged.

FIG. 82 shows a controller, in accordance with one or more embodimentsof the present disclosure. In some cases, a controller may monitorand/or control various operational parameters. In some cases, acontroller may monitor and/or control a flow rate of ammonia into asystem, a flow rate of gas into a fuel cell, a flow rate of air into acombustor, any flow into or out of a system or system componentdisclosed herein, or any combination thereof. In some cases, acontroller may monitor and/or control a temperature of a reactor (e.g.,an electrical reactor or a combustor reactor), a fuel cell, a heatexchanger, flows between components of the system, any system component,or any combination thereof. In some cases, a controller may monitorand/or control one or more valves, one or more pumps, one or more fans,one or more blowers, one or more compressors, or any combination thereofto adjust an ammonia flow rate, a flow rate of a gas into a fuel cell,flow rate from an air supply unit, any flow into or out of a system orsystem component disclosed herein, or any combination thereof. In somecases, a controller may monitor and/or control a power output or inputof one or more system components disclosed herein, for example, one ormore fuel cells, one or more heaters, or any combination thereof. Insome cases, a controller may monitor and/or control a concentration of asubstance in an environment or within a system, for example, humidity,ammonia concentration, hydrogen, or any combination thereof in theenvironment or in any system component or flows between disclosedherein. In some cases, a controller may monitor and/or control apressure of a system component or any flows in between, for example, areactor, a fuel cell, ammonia storage tank, and any flows in between. Insome cases, a controller may be communicatively coupled to one or moreoptional monitors (i.e., sensors). In some cases, a controller may becommunicatively coupled to one or more optional monitors in addition toa preferred monitor and controls. In some cases, a controller may becommunicatively coupled to two or more optional monitors.

Hybrid Heating

FIG. 14 schematically illustrates an example of a main reactor withhybrid heating, in accordance with one or more embodiments of thepresent disclosure. Such a hybrid heating design may improve heattransfer while minimizing reactor heat loss and may decrease startuptime. The hybrid heating design may also reduce a weight and a volume ofthe reactor and improve thermal management characteristics of the systemwhile providing an optimized heat source for ammonia conversion.

The hybrid heating design for the main reactor may comprise one or moreheat sources. The heat sources may be, for example, the heating unitsdescribed elsewhere herein. The heat sources may comprise the startupheating and reforming unit and/or the one or more main heating units. Insome cases, the one or more heat sources may comprise two or more heatsources or heating units. In some cases, the two or more heat sourcesmay be the same. In other cases, the two or more heat sources may bedifferent. For example, a first heat source may be configured for jouleheating, and a second heat source may be configured for combustionheating. In some cases, the hybrid heating reactor may comprise aseparator (e.g., a physical component or structure) that is providedbetween the first heat source and the second heat source. The separatormay or not may not facilitate a transfer of thermal energy across theseparator.

In one example, the main reactor with the hybrid heating design may beconfigured to receive ammonia through an inlet. The ammonia may bedirected through the main reactor, which may comprise a catalystmaterial that is heated using the two or more heat sources. The catalystmaterial may be heated directly or indirectly using the first heatsource when the ammonia is directed through a first portion of the mainreactor. The catalyst material may be heated directly or indirectlyusing the second heat source when the ammonia is directed through asecond portion of the main reactor. Heating the catalyst material in thepresence of the ammonia may produce hydrogen and/or nitrogen. Thehydrogen and/or nitrogen may then be directed towards an outlet, whichmay be in fluid communication with one or more hydrogen fuel cells. Insome embodiments, the hydrogen and/or nitrogen may be directed towardsan outlet, which may be in fluid communication with one or morecombustion engines and/or combustors.

In some embodiments, the main reactor with the hybrid heating design maybe configured to combust leftover hydrogen gas from the reactor (e.g.,the main reactor or the fast startup reactor) or from one or more fuelcells to heat the ammonia and/or the catalyst material. In some cases,the reactor walls or fluid channel walls may be designed to permit heatexchange across the walls of the reactor or between the fluid flows. Insome cases, the heat sources or heating units may comprise a powdermaterial with a high heat transfer coefficient to enhance heat transfer.In some cases, a heat exchanger may be incorporated into or integratedwith one or more components of the main reactor, which may result in themain reactor being more compact and efficient. Further, the main reactormay comprise one or more walls with a thickness ranging from about 0.5millimeters to about 1.2 millimeters, which may reduce thermal mass. Insome embodiments, the main reactor may comprise one or more walls with athickness ranging from about 1 millimeters to about 30 millimeters,which may increase structural integrity. The main reactor with thehybrid heating design may be configured to minimize heat loss whileproviding fast hydrogen extraction and fast load following.

FIG. 15A schematically illustrates reactor thermal reforming efficiency,endothermicity fraction, and hydrogen combustion fraction data for thesystems and methods of the present disclosure. Hybrid heating of thereactor may provide higher thermal reforming efficiency compared toother conventional reactors across a variety of different ammonia flowrates. Further, the hybrid heating reactor systems disclosed hereinexhibit a more favorable endothermicity fraction compared to otherconventional reactors. In some cases, integrating or incorporating aheat exchanger with the hybrid heating reactor may further improve ahydrogen combustion fraction for the hybrid heating reactor.

FIG. 15B schematically illustrates additional data for reactor thermalreforming efficiency, endothermicity/heat in fraction, and fuel cellpower output in watts, as a function of ammonia flow rate, for variousheating power ranging from 100 watts to 600 watts. As used herein,reactor thermal reforming efficiency may correspond to a ratio of usablechemical energy out (e.g. H₂) to chemical energy (NH₃) and heat energyinto the reactor. In some cases, the reactor thermal reformingefficiency may reach about 90% for ammonia flow rates ranging from about10 liters per minute to about 20 liters per minute, when a heating powerof 300 watts, 400 watts, 500 watts, or 600 watts is provided to thereactor. As used herein, endothermicity fraction may correspond to theamount of heat energy absorbed by the reactor during an endothermicreaction over the total amount of heat or thermal energy into the system(i.e., the total amount of heat or thermal energy provided or suppliedto the reactor or the catalyst bed by one or more heating units). Insome cases, the endothermicity fraction may reach about 0.5 for ammoniaflow rates ranging from about 10 liters per minute to about 20 litersper minute, when a heating power of 300 watts, 400 watts, 500 watts, or600 watts is provided to the reactor. The power output of the one ormore fuel cells described herein may reach about 2 kilowatts (kW) forammonia flow rates ranging from about 15 liters per minute to about 20liters per minute, when a heating power of 600 watts is provided to thereactor.

FIG. 16 schematically illustrates hybrid heating simulation data for thesystems and methods of the present disclosure. As described elsewhereherein, the hybrid heating reactor may comprise two or more heatersconfigured for different modes of heating (e.g., combustion or jouleelectrical heating). The hybrid heating reactor may exhibit a heatingpower ratio (R) that ranges from 0 to 1. A heating power ratio of 0indicates that all power is provided to a first heater of the hybridheating reactor, whereas a power ratio of 1 indicates that all power isprovided to a second heater of the hybrid heating reactor. A power ratioof 0.5 indicates that power is provided equally to the first heater andthe second heater. The heating power ratio (R) for the reactor may bedetermined as follows:

-   P_heater_1 = P_total*(R)-   P_heater_2 = P_total*(1-R)

The hybrid heating data shown in FIG. 16 was generated based on a totalheating power (P_total) of 315 watts of thermal energy and an ammoniamass flow rate of 0.1 grams per second. The hybrid heating data showssignificantly different heat utilization with different heating powerratios.

FIG. 17 schematically illustrates heating power ratio simulation datafor the systems and methods of the present disclosure. Due todifferences in heat utilization, ammonia conversion efficiencies maychange based on the heating power ratio. The heating power ratio may berepresented as a ratio between combustion and joule heating. As theheating power ratio increases, the ammonia conversion efficiency mayalso increase (e.g., linearly and/or proportionally).

In another aspect, the present disclosure provides a system comprising areactor module configured to receive a source material comprisingammonia. The reactor module may comprise a catalyst and a plurality ofheating units for heating the catalyst. In some embodiments, theplurality of heating units may comprise a first heating unit configuredto heat at least a first portion of the catalyst by combusting hydrogenand a second heating unit configured to heat at least a second portionof the catalyst using electrical heating. The term “electrical heating,”as used herein, generally refers to heating performed at least in partby flowing electrons through a material (e.g., an electrical conduit).The electrical conduit may be a resistive load. In some examples,electrical heating may comprise Joule heating (i.e., heating thatfollows Ohm’s law). Joule heating, also known as resistive, resistance,or Ohmic heating, may comprise passing an electric current through amaterial (e.g., the electrical resistor, the catalyst, the catalystmaterial, or the catalyst bed) to produce heat or thermal energy. Insome cases, the catalyst may be used to generate hydrogen from thesource material comprising the ammonia when the catalyst is heated usingthe plurality of heating units. In some embodiments, the first portionand the second portion may be the same portion of the catalyst. In otherembodiments, the first portion and the second portion may be differentportions of the catalyst. In some cases, the first portion and thesecond portion may overlap or partially overlap.

In some cases, the first heating unit of the reactor module may beconfigured to heat a first portion of the catalyst based on a combustionof hydrogen gas generated using the secondary reactor module. In somecases, the first heating unit may be configured to heat the firstportion of the catalyst based on a combustion of leftover hydrogen gasfrom (i) one or more fuel cells in fluid communication with the reactormodule or (ii) a secondary reactor module (e.g., the fast startupreactor module described elsewhere herein). In some cases, the secondheating unit may be configured to heat a second portion of the catalystby passing an electrical current through the second portion of thecatalyst. In some cases, the first portion of the catalyst and thesecond portion of the catalyst may be contiguous (i.e., physicalconnected). In other cases, the first portion of the catalyst and thesecond portion of the catalyst may be separated by a third portion ofthe catalyst. The third portion of the catalyst may be positionedbetween the first and second portions of the catalyst. In some cases,the first and second portions of the catalyst may be in thermalcommunication with each other (either directly or indirectly via thethird portion of the catalyst). In other cases, the first and secondportions of the catalyst may not or need not be in thermal communicationwith each other.

In some embodiments, the system may further comprise a secondary reactormodule in fluid and/or thermal communication with the reactor module.The secondary reactor module may comprise a secondary catalyst and asecondary heating unit. The secondary heating unit may be configured toheat the secondary catalyst. In some cases, the secondary heating unitmay comprise one or more electrodes for passing a current through thesecondary catalyst to heat the secondary catalyst. The secondarycatalyst may be used to generate hydrogen from ammonia when thesecondary catalyst is heated using the secondary heating unit.

In some embodiments, the heat load distribution between the firstheating unit and the second heating unit of the main reactor may beadjustable to increase an ammonia conversion efficiency and/or toenhance a thermal efficiency of the reactor module. The heat loaddistribution may comprise a heating power ratio corresponding to a ratiobetween a heating power of the first heating unit and a heating power ofthe second heating unit. The heating power of the first heating unit andthe second heating unit may be adjusted in order to achieve a desiredammonia conversion efficiency and thermal efficiency. In some cases, thesystem may further comprise a controller or processor configured tocontrol an operation of the first heating unit and the second heatingunit to adjust the heat load distribution within the reactor module. Insome cases, such adjustments in the heat load distribution may beimplemented in real-time based on one or more sensor measurements (e.g.,temperature measurements) or based on a performance of the reactormodule (e.g., ammonia conversion efficiency and/or thermal efficiency ofthe reactor module). In some cases, heaters with two or more heatingzones may be used to control power and heat distribution within theheater. In some cases, the system may comprise a plurality of heatingunits. The plurality of heating units may comprise at least two or moreheating units. In some cases, a heat load distribution between the atleast two or more heating units may be adjustable to increase an ammoniaconversion efficiency and to enhance a thermal reforming efficiency ofthe reactor module. In some cases, each of the at least two or moreheating units may have one or more heating zones in the reactor moduleto allow for a continuous heat distribution within one or more regionsin the reactor module. In some cases, the at least two or more heatingunits may be configured to heat different zones in the reactor module.In some cases, the at least two or more heating units may be configuredto heat one or more same zones in the reactor module.

In some embodiments, the reactor module may comprise a reaction bedcomprising one or more ammonia decomposition catalysts comprising ametal material, a promoter material, and a support material. The firstheating unit and the second heating unit may be configured to heatdifferent portions of the reaction bed. In some cases, the metalmaterial may comprise, for example, ruthenium, nickel, rhodium, iridium,cobalt, iron, platinum, chromium, palladium, or copper. In someembodiments, the promoter material may comprise at least one materialselected from Li, Na, K, Rb, Cs, Mg, Ca, Ba, Sr, La, Ce, Pr, Sm, or Gd.In some embodiments, the support may comprise at least one materialselected from Al₂O₃, MgO, CeO₂, ZrO₂, La₂O₃, SiO₂, Y₂O₃, TiO₂, SiC,hexagonal BN (boron nitride), BN nanotubes, silicon carbide, one or morezeolites, LaAlO₃, CeAlO₃, MgAl₂O₄, CaAl₂O₄, or one or more carbonnanotubes.

In some embodiments, the reactor module may comprise a cartridge heaterdesign that utilizes one or more electrical insulation materials with ahigh heat transfer coefficient. In some cases, the one or moreelectrical insulation materials may comprise, for example, boronnitride.

In some embodiments, the reactor module may comprise one or more wallshaving a thickness that ranges from about 0.5 millimeters to about 1.5millimeters to reduce thermal mass and to provide a faster and moredynamic temperature response. In some embodiments, the reactor modulemay comprise one or more walls having a thickness that ranges from about1.5 millimeters to about 30 millimeters to increaser the structuralintegrity. In some embodiments, the reactor module may have a thermalreforming efficiency of at least about 90%. In some cases, the reactormodule may have a thermal reforming efficiency of at least about 95%. Asused herein, the term “thermal efficiency” or “thermal reformingefficiency” may refer to a percentage of the total thermal and chemicalenergy provided to a system that gets converted to chemical energy ofH₂. In some cases, “thermal efficiency” or “thermal reformingefficiency” may correspond to a heating value of hydrogen over a heatingvalue of ammonia and an actual heat input. In some cases, “thermalefficiency” or “thermal reforming efficiency” may correspond to H₂chemical energy out over NH₃ chemical energy in plus heat in.

In some cases, the system may further comprise one or more fuel cells influid communication with the reactor module. The one or more fuel cellsmay be configured to generate electrical energy using the hydrogengenerated by the reactor module. In some cases, the one or more fuelcells may be in fluid communication with the reactor module and/or thesecondary reactor module. The secondary reactor module may comprise, forexample, the fast startup reactor module described above. The one ormore fuel cells may be configured to generate electrical energy usingthe hydrogen generated by the reactor module and/or the secondaryreactor module.

Methods

In another aspect, the present disclosure provides a method forprocessing ammonia to generate hydrogen. The method may compriseproviding a source material comprising ammonia to a first reactormodule. The first reactor module may comprise a first catalyst and astartup heating and reforming unit. The startup heating and reformingunit may comprise one or more electrodes for passing a current throughthe first catalyst to heat the first catalyst. The method may furthercomprise heating the first catalyst by using the startup heating andreforming unit to pass a current through at least a portion of the firstcatalyst. The first catalyst may be used to generate hydrogen from theammonia when the first catalyst is heated using the startup heating andreforming unit.

In some embodiments, the method may comprise providing the hydrogengenerated using the first reactor module to one or more fuel cells. Themethod may further comprise using the one or more fuel cells to generateelectricity.

In other embodiments, the method may comprise providing the hydrogengenerated using the first reactor module to a second reactor module thatis in fluid communication with the first reactor module. The secondreactor module may also be configured to receive a source materialcomprising ammonia. The source material may be provided to the firstreactor module and the second reactor module from a same source. In somecases, the source material may be provided to the first reactor moduleand the second reactor module from different sources. The second reactormodule may comprise a second catalyst and one or more main heating unitsfor heating the second catalyst. The method may further comprise heatingat least a portion of the second catalyst using the one or more mainheating units. In some cases, the method may comprise heating the secondcatalyst by combusting at least a portion of the hydrogen generated bythe first reactor module. Once heated, the second catalyst may be usedto generate additional hydrogen from the ammonia received by the secondreactor module.

In some embodiments, the method may further comprise providing thehydrogen generated using the second reactor module to one or more fuelcells. In some cases, the method may further comprise using the one ormore fuel cells to generate electricity. The electricity may be used topower one or more systems or devices requiring electrical power tooperate (e.g., various terrestrial, aerial, or aquatic vehicles).

In another aspect, the present disclosure provides a method forprocessing ammonia to generate hydrogen. The method may compriseproviding a source material comprising ammonia to a reactor module. Thereactor module may comprise a catalyst and a plurality of heating unitsfor heating the catalyst. The plurality of heating units may comprise afirst heating unit configured to heat at least a first portion of thecatalyst by combustion and a second heating unit configured to heat atleast a second portion of the catalyst using Joule heating. In somecases, the first portion and the second portion of the catalyst may becontiguous or adjacent to each other. In other cases, the first portionand the second portion of the catalyst may be separated by a thirdportion of the catalyst, or a barrier (e.g., a physical barrier or athermal barrier).

In some embodiments, the method may further comprise heating a firstportion of the catalyst by combusting hydrogen. In some embodiments, themethod may further comprise heating a second portion of the catalyst bypassing a current through the second portion of the catalyst. Onceheated, the catalyst may be used to generate hydrogen from the sourcematerial comprising the ammonia. In some cases, the hydrogen that iscombusted to heat the first portion of the catalyst may be generatedusing a secondary reactor module. Such secondary reactor module may beconfigured to generate (i.e., produce or extract) the hydrogen from asource material comprising ammonia. The secondary reactor module maycomprise a secondary catalyst and a secondary heating unit. In somecases, the secondary heating unit may be configured to heat thesecondary catalyst by passing a current through the secondary catalyst.Once heated, the secondary catalyst may be used to generate hydrogenfrom the source material received by the secondary reactor module.

In some embodiments, the method may further comprise providing thehydrogen generated using the reactor module to one or more fuel cells.In some cases, the method may further comprise using the one or morefuel cells to generate electricity. The electricity may be used to powerone or more systems or devices requiring electrical power to operate(e.g., various terrestrial, aerial, or aquatic vehicles).

In some embodiments, the method may further comprise providing thehydrogen generated using the reactor module to one or more combustionengines. In some cases, the method may further comprise using the one ormore combustion engines to generate mechanical work. The mechanical workmay be used to power one or more systems or devices requiring power tooperate (e.g., various terrestrial, aerial, or aquatic vehicles).

Computer Systems

In an aspect, the present disclosure provides computer systems that areprogrammed or otherwise configured to implement methods of thedisclosure. FIG. 18 shows a computer system 1801 (i.e., a controller orcomputing device) that may be programmed or otherwise configured toimplement a system and/or method for processing ammonia. The computersystem 1801 may be configured to, for example, (i) control a flow of asource material comprising ammonia to one or more reactors, (ii) controlan operation of one or more heating units to heat one or more catalystsof the one or more reactors, which one or more catalysts may be used togenerate hydrogen from the source material comprising the ammonia afterbeing heated by the one or more heating units, and (iii) control a flowof hydrogen generated from the ammonia to one or more fuel cells togenerate electricity. The computer system 1801 may control a flow of thesource material to the reactors and/or a flow of the hydrogen from thereactors to the one or more fuel cells by modulating one or more flowcontrol mechanisms (e.g., one or more valves). The computer system 1801may control an operation of the one or more heating units by modulatingan amount of current that is passed through the one or more catalysts.The computer system 1801 may be an electronic device of a user or acomputer system that is remotely located with respect to the electronicdevice. The electronic device may be a mobile electronic device.

The computer system 1801 may include a central processing unit (CPU,also “processor” and “computer processor” herein) 1805, which may be asingle core or multi core processor, or a plurality of processors forparallel processing. The computer system 1801 also may include memory ormemory location 1810 (e.g., random-access memory, read-only memory,flash memory), electronic storage unit 1815 (e.g., hard disk, solidstate disk, etc.), communication interface 1820 (e.g., network adapter)for communicating with one or more other systems, and peripheral devices1825, such as cache, other memory, data storage and/or electronicdisplay adapters. The memory 1810, storage unit 1815, interface 1820 andperipheral devices 1825 are in communication with the CPU 1805 through acommunication bus (solid lines), such as a motherboard. The storage unit1815 may be a data storage unit (or data repository) for storing data.The computer system 1801 may be operatively coupled to a computernetwork (“network”) 1830 with the aid of the communication interface1820. The network 1830 may be the Internet, an internet and/or extranet,or an intranet and/or extranet that is in communication with theInternet. The network 1830 in some cases may be a telecommunicationand/or data network. The network 1830 may include one or more computerservers, which may enable distributed computing, such as cloudcomputing. The network 1830, in some cases with the aid of the computersystem 1801, may implement a peer-to-peer network, which may enabledevices coupled to the computer system 1801 to behave as a client or aserver.

The CPU 1805 may execute a sequence of machine-readable instructions,which may be embodied in a program or software. The instructions may bestored in a memory location, such as the memory 1810. The instructionsmay be directed to the CPU 1805, which may subsequently program orotherwise configure the CPU 1805 to implement methods of the presentdisclosure. Examples of operations performed by the CPU 1805 may includefetch, decode, execute, and writeback.

The CPU 1805 may be part of a circuit, such as an integrated circuit.One or more other components of the system 1801 may be included in thecircuit. In some cases, the circuit may be an application specificintegrated circuit (ASIC).

The storage unit 1815 may store files, such as drivers, libraries andsaved programs. The storage unit 1815 may store user data, e.g., userpreferences and user programs. The computer system 1801 in some casesmay include one or more additional data storage units that are locatedexternal to the computer system 1801 (e.g., on a remote server that isin communication with the computer system 1801 through an intranet orthe Internet).

The computer system 1801 may communicate with one or more remotecomputer systems through the network 1830. For instance, the computersystem 1801 may communicate with a remote computer system of a user(e.g., an individual operating the reactor, an entity monitoring theoperation of the reactor, or an end user operating a device or a vehiclethat may be powered using electrical energy derived or produced from thehydrogen generated using the reactor). Examples of remote computersystems include personal computers (e.g., portable PC), slate or tabletPC’s (e.g., Apple® iPad, Samsung® Galaxy Tab), telephones, Smart phones(e.g., Apple® iPhone, Android-enabled device, Blackberry®), or personaldigital assistants. The user may access the computer system 1801 via thenetwork 1830.

Systems and methods as described in the present disclosure may beimplemented by way of machine (e.g., computer processor) executable codestored on an electronic storage location of the computer system 1801,such as, for example, on the memory 1810 or electronic storage unit1815. The machine executable or machine readable code may be provided inthe form of software. During use, the code may be executed by theprocessor 1805. In some cases, the code may be retrieved from thestorage unit 1815 and stored on the memory 1810 for ready access by theprocessor 1805. In some cases, the electronic storage unit 1815 may beprecluded, and machine-executable instructions are stored on memory1810.

The code may be pre-compiled and configured for use with a machinehaving a processor adapted to execute the code, or may be compiledduring runtime. The code may be supplied in a programming language thatcan be selected to enable the code to execute in a pre-compiled oras-compiled fashion.

Aspects of the systems and methods provided herein, such as the computersystem 1801, may be embodied in programming. Various aspects of thetechnology may be thought of as “products” or “articles of manufacture”typically in the form of machine (or processor) executable code and/orassociated data that is carried on or embodied in a type of machinereadable medium. Machine-executable code may be stored on an electronicstorage unit, such as memory (e.g., read-only memory, random-accessmemory, flash memory) or a hard disk. “Storage” type media may includeany or all of the tangible memory of the computers, processors or thelike, or associated modules thereof, such as various semiconductormemories, tape drives, disk drives and the like, which may providenon-transitory storage at any time for the software programming. All orportions of the software may at times be communicated through theInternet or various other telecommunication networks. Suchcommunications, for example, may enable loading of the software from onecomputer or processor into another, for example, from a managementserver or host computer into the computer platform of an applicationserver. Thus, another type of media that may bear the software elementsincludes optical, electrical and electromagnetic waves, such as usedacross physical interfaces between local devices, through wired andoptical landline networks and over various air-links. The physicalelements that carry such waves, such as wired or wireless links, opticallinks or the like, also may be considered as media bearing the software.As used herein, unless restricted to non-transitory, tangible “storage”media, terms such as computer or machine “readable medium” refer to anymedium that participates in providing instructions to a processor forexecution.

Hence, a machine readable medium, such as computer-executable code, maytake many forms, including but not limited to, a tangible storagemedium, a carrier wave medium or physical transmission medium.Non-volatile storage media including, for example, optical or magneticdisks, or any storage devices in any computer(s) or the like, may beused to implement the databases, etc. shown in the drawings. Volatilestorage media may include dynamic memory, such as main memory of such acomputer platform. Tangible transmission media may include coaxialcables; copper wire and fiber optics, including the wires that comprisea bus within a computer system. Carrier-wave transmission media may takethe form of electric or electromagnetic signals, or acoustic or lightwaves such as those generated during radio frequency (RF) and infrared(IR) data communications. Common forms of computer-readable mediatherefore may include for example: a floppy disk, a flexible disk, harddisk, magnetic tape, any other magnetic medium, a CD-ROM, DVD orDVD-ROM, any other optical medium, punch cards paper tape, any otherphysical storage medium with patterns of holes, a RAM, a ROM, a PROM andEPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wavetransporting data or instructions, cables or links transporting such acarrier wave, or any other medium from which a computer may readprogramming code and/or data. Many of these forms of computer readablemedia may be involved in carrying one or more sequences of one or moreinstructions to a processor for execution.

The computer system 1801 may include or be in communication with anelectronic display 1835 that comprises a user interface (UI) 1840 forproviding, for example, a portal for a user to monitor or track anoperation or a performance of the one or more reactors, or one or morecomponents of the reactors. In some cases, the performance of the one ormore reactors may comprise, for example, an ammonia conversionefficiency or a thermal efficiency of the one or more reactors. Theportal may be provided through an application programming interface(API). A user or entity may also interact with various elements in theportal via the UI. Examples of UI’s include, without limitation, agraphical user interface (GUI) and web-based user interface.

Methods and systems of the present disclosure may be implemented by wayof one or more algorithms. An algorithm may be implemented by way ofsoftware upon execution by the central processing unit 1805. Forexample, the algorithm may be configured to control an operation of theone or more reactors based on one or more sensor readings (e.g.,temperature measurements, flow rates, etc.), or based on a performanceof the one or more reactors. In some cases, the algorithm may beconfigured to (i) control a flow of a source material comprising ammoniato one or more reactors, (ii) control an operation of one or moreheating units to heat one or more catalysts of the one or more reactors,the one or more catalysts being capable of producing or extractinghydrogen from the source material comprising the ammonia after beingheated by the one or more heating units, and/or (iii) control a flow ofhydrogen generated from the ammonia to one or more fuel cells togenerate electricity. In some cases, the algorithm may be configured tocontrol, modify, or adjust the heat load distribution between a firstheating unit and a second heating unit of the reactor to increase anammonia conversion efficiency and to enhance a thermal efficiency of thereactor module. The heat load distribution may comprise a heating powerratio corresponding to a ratio between a heating power of the firstheating unit and a heating power of the second heating unit. Thealgorithm may use various monitor or sensor readings or variousparameters associated with a performance of the reactors to adjust theheating power of the first heating unit and the second heating unit inorder to achieve a desired ammonia conversion efficiency and/or reactorthermal efficiency.

System Configurations

FIG. 19 illustrates a compact ammonia powerpack system comprising a heatexchanger for exit flows from the main reactor R_m. The exit flow fromthe main reactor R_m may be cooled using the heat exchanger (HX) beforeentering an adsorption tower (ADS). The heat exchanger may be used tofacilitate a transfer of thermal energy between the exit flow (which maycomprise hydrogen, nitrogen, and/or a low ppm of unconverted ammonia)and a heat sink (e.g., ammonia storage tank) or a fluid medium (e.g.,ambient air). The heat exchanger may be in thermal communication withambient air to cool the exit flow from the main reactor R_m to less thanabout 50° C. Alternatively, the heat exchanger may be in thermalcommunication with one or more ammonia storage tanks to cool the exitflow from the main reactor R_m to less than about 50° C. and to provideheating energy for ammonia evaporation in the storage tanks.Alternatively, the heat exchanger may be in thermal communication withone or more ammonia inflows to cool the exit flow from the main reactorR_m to less than about 50° C. and to provide heat or thermal energy forammonia evaporation in the heat exchanger. The cooled exit flow may bedirected to one or more adsorption towers to remove any traces ofammonia from the cooled exit flow before the exit flow is directed toone or more fuel cells. The adsorption towers may help to preserve aperformance and/or a longevity of the one or more fuel cells sinceammonia can be detrimental to the performance of fuel cells. Theadsorption towers may comprise one or more adsorbents which may bereplaceable (e.g., a cartridge form factor) after a certain number ofcycles or operations. The one or more adsorbents may be configured tofilter out or remove unconverted ammonia and/or nitrogen from an exitflow from the one or more reactors.

FIG. 20 illustrates an ammonia powerpack system comprising a heatexchanger for cooling the exit flows of the main reactor R_m using theinlet flows. The heat exchanger may be in thermal communications withthe ammonia storage tank to facilitate cooling of the exit flow from R_mand to provide thermal energy for ammonia evaporation in the storagetank. In some embodiments, the ammonia storage tank may be in thermalcommunications with the fuel cell to recover waste heat from the fuelcell to provide heating energy for the ammonia evaporation within theammonia storage tank. The inlet and exit flows of the reactor may be inthermal communication with each other via the heat exchanger for heatrecovery. In some cases, the inlet flows (which may comprise ammoniafrom one or more ammonia tanks) may be heated or pre-heated beforeentering the main reactor R_m. The inlet flows may be heated orpre-heated via a transfer of thermal energy between the inlet flows andthe exit flows. The exit flows may comprise hydrogen and/or nitrogenthat is produced by a decomposition of the ammonia in the inlet flows.The transfer of thermal energy between the exit flows and the inletflows and/or the ammonia storage tank may cool the exit flows before theexit flows enter an adsorption tower that is upstream of one or morefuel cells configured to utilize at least a portion of the exit flows(e.g., hydrogen) to generate electrical energy.

FIG. 21 illustrates an ammonia powerpack system comprising a heatexchanger for cooling both inlet flows and exit flows of the mainreactor R_m. The ammonia powerpack system may further comprise a startupreactor R_s as described elsewhere herein. The startup reactor may beconfigured to decompose ammonia within a predetermined amount of time ofstarting the reactor. The predetermined amount of time may be at mostabout 5 minutes or less. In some embodiments, the predetermined amountof time may be at most about 60 minutes or less. The startup reactor maybe powered by electrical energy (e.g., by passing a current through anelectrically conductive catalyst material for heat generation). Thestartup reactor may comprise a catalyst that is configured to decomposeammonia when heated to a threshold temperature (e.g., above 350°Celsius). The decomposition of the ammonia may produce hydrogen, whichmay be directed from the startup reactor R_s to the heating units of themain reactor R_m for combustion heating, as described elsewhere herein.In some cases, during high power demands, the startup reactor mayoperate as a load following unit. The inlet flows into the main reactorR_m may comprise ammonia, nitrogen, and/or hydrogen. The inlet flowsinto the main reactor R_m may comprise ammonia from one or more ammoniatanks, or nitrogen, hydrogen, and/or unconverted ammonia from thestartup reactor R_s.

FIG. 22 illustrates an ammonia power pack to power a larger system(e.g., a system with power requirements of at least about 100 kilowattsor more). The power pack system may comprise a startup reactor R_s, amain reactor R_m, and a plurality of adsorbent towers (ADS). In somecases, the adsorbent towers may comprise an adsorbent material providedin a cartridge form factor. However, the adsorbent material may not orneed not be in a cartridge form factor. In some cases, a two adsorbentbed may be utilized for on-demand adsorbent regeneration and continuousoperation of the ammonia powerpack system. In some instances, a firstadsorbent tower may be used or operated for a first time period, and asecond adsorbent tower may be on standby ready to be used or operated.Once the first ADS is fully discharged, the system may switch a flowpath of the exit flow from the main reactor R_m to the second ADS. Thesecond ADS may be used to remove any traces of ammonia from the exitflow before the exit flow is directed to the one or more fuel cells.While the second ADS is being used, the first ADS may be regenerated.Once the second ADS is fully discharged, the first ADS may beregenerated and ready for use in another cycle or operation. In any ofthe embodiments described herein, two, three, four, five, six, seven,eight, nine, ten, or more adsorption towers may be used.

As shown in FIG. 23 , in some cases one or more additional heatexchangers may be provided. The one or more additional heat exchangersmay be used to regenerate the various adsorbent beds. For example,adsorbent bed 1 (ADS_1) may be regenerated using an embedded electricalheater (H_3). A pump or blower may be used to remove regenerated ammoniaand to combine a stream of the regenerated ammonia with an exit flowfrom a fuel cell (which may comprise unconverted H₂ and/or N₂). Theammonia may be dumped into the fuel cell exit stream. The fuel cell exitstream and ammonia combination may be directed to the main reactor R_mfor combustion in order to heat the main reactor R_m for further ammoniadecomposition.

After the adsorbent is regenerated, the adsorbent bed may be cooled downfor a following cycle. For example, when adsorbent bed 2 (ADS_2) isbeing regenerated, the fluid flow path between ADS_2 may be closed orrestricted using a valve, and the fluid path designated with a dottedline (i.e., the dotted line between ADS_2 and the pump or blower P) maypermit regenerated ammonia from ADS_2 to be directed towards acombustion reaction stream that is provided to H_2 for combustionheating of main reactor R_m. In such cases, ADS_1 may then permit theflow of the main reactor R_m exit flow through ADS_1 towards the fuelcell.

As shown in FIG. 24 , in some cases one or more additional heatexchangers may be provided. The one or more additional heat exchangersmay be used to regenerate the various adsorbent beds. For example,adsorbent bed 1 may be regenerated using an embedded combustion heater(H_3). In some cases, combusted byproducts from H_3, mostly water vapor,may be dumped to the atmosphere. A pump or blower may be used to removeregenerated ammonia and to combine a stream of the regenerated ammoniawith an exit flow from the fuel cell (which may comprise unconverted H₂and/or N₂). The ammonia may be dumped into the fuel cell exit stream.The fuel cell exit stream and ammonia combination may be directed to themain reactor R_m for combustion in order to heat the main reactor R_m,removal of the desorbed ammonia from adsorbents, and/or for furtherammonia decomposition. In some embodiments, exhaust streams from the oneor more combustion reactors or heaters (e.g., H_2 in FIG. 24 ), may beused for adsorbent regeneration.

In some cases, ambient air (e.g., a portion of air from the main reactor(R_m) combustor heater (H_2) air intake) and the H₂ and/or N₂ from thefuel cell exit flow may be drawn or directed to the adsorbent combustionheaters H_3 for regeneration. In some cases, one or more flow controlunits (e.g., valves) may be used to direct the fuel cell exit flow todifferent combustion heaters H_3. In some embodiments, regeneratedammonia, unconverted hydrogen, and/or nitrogen exiting from a firstadsorbent combustion heater H_3 may be vented to ambient. After the oneor more adsorbent beds are regenerated, the adsorbent beds may be cooleddown for one or more following cycles, thereby enabling continuousoperation.

As shown in FIG. 25 , in some cases three or more adsorption towers maybe used in a single ammonia powerpack system. The powerpack systemillustrated in FIG. 25 may be adapted for larger system configurations(e.g., electrical vehicles with a power requirement of 100 kW or more).In some configurations, a two adsorbent bed may be available foron-demand adsorbent regeneration and continuous operation. One moreadditional adsorbent beds (e.g., ADS_3) may be utilized as a safetyfeature for the fuel cell (e.g., in case regeneration of ADS_1 and ADS_2are incomplete during operation of the ammonia powerpack system). Insome cases, the adsorbent material in ADS_1 and ADS_2 may be the same,and the adsorbent material in ADS_3 may be different than that of ADS_1and ADS_2. In some embodiments, a combination of different adsorbentmaterials may be used to increase the NH₃ adsorption efficiency orcapacity of the overall system.

Additional Embodiments

In some cases, the ammonia powerpack system may comprise a startupreactor for dynamic load following (e.g., by controlling ammonia flowrates and electrical heating). In some cases, the ammonia powerpacksystem may comprise a main reactor for dynamic load following (e.g., bycontrolling ammonia flow rates, and the amount of H₂ combustion orelectrical heating or a combination of both).

In some cases, the ammonia powerpack system may comprise an electricbattery for dynamic load following. The main reactor may be configuredto maintain constant power output, and an on-board electric battery mayprovide dynamic load following capabilities, (i.e., discharges when loadis high and charges when load is low).

In some cases, the ammonia powerpack system may comprise an emergencyshut off capability. The emergency shut off capability may beimplemented using a sensor that is configured to monitor ammonia ppmlevels at the adsorbent bed inlet and fuel cell inlet, and shut off orreduce ammonia flow rates if the ammonia ppm level is above a certainthreshold limit (e.g., ~10 ppm for fuel cell inlet).

In some cases, the ammonia powerpack system may comprise an adsorbentswitch with one or more embedded ammonia sensors. The ammonia sensorsmay be configured to monitor ammonia concentration within the adsorbent.The N₂ and/or H₂ exit flow from the reactor may switch to the nextadsorbent when ammonia levels are above a certain threshold level (e.g.,at least about 10 ppm).

In some cases, the adsorbent material may comprise a combination ofadsorbents (e.g., zeolites) and metal salts (e.g., MgCl2), which mayfurther lower the ammonia ppm level of the main reactor exit flow.

In some cases, the ammonia powerpack system may permit ammonia flowcontrol in order to maintain and/or adjust reactor temperatures (e.g.,an increase in ammonia flow rate may decrease the reactor temperature).This control may prevent or reduce the risk of overheating and maintainan optimal temperature for ammonia decomposition.

In any of the embodiments described herein, the ammonia power pack unitmay comprise one or more reactors and one or more fuel cells attached,secured or affixed to a common frame so that the reactor(s) and the fuelcell(s) may be configured to operate as an integrated powerpack system.

Packaging and Assembly

In another aspect, the present disclosure provides various exemplaryconfigurations for packaging and assembly of ammonia powerpack systems.The ammonia powerpack systems may have any of the components or systemconfigurations described elsewhere herein.

As shown in FIG. 26 , in some cases the ammonia powerpack system maycomprise one or more fuel cell units. The ammonia powerpack system mayfurther comprise one or more ammonia tanks coupled to or positionedadjacent to the one or more fuel cell units. In some cases, the one ormore ammonia tanks may be placed on top of the one or more fuel cellunits. The ammonia powerpack system may further comprise a main reactorR_m and a startup reactor R_s as described above. The ammonia tank maybe in fluid communication with the main reactor R_m and/or the startupreactor R_s. Ammonia may flow from the ammonia tank to the startupreactor R_s and/or the main reactor R_m. The main reactor R_m and thestartup reactor R_s may be coupled to or positioned adjacent to one ormore sides of the fuel cell unit. In some cases, the main reactor R_mand the startup reactor R_s may be positioned on different sides of thefuel cell unit. The main reactor R_m and the startup reactor R_s may bein fluid communication with each other such that one or more fluids ormaterials from the startup reactor R_s may flow to the main reactor R_m.In some cases, the fuel cell unit may also be in fluid communicationwith the main reactor R_m. In some cases, unconverted hydrogen from thefuel cell unit may be directed to the main reactor R_m for combustionheating to heat the main reactor. In some cases, a battery unit may beoperatively coupled to the fuel cell unit, the main reactor R_m, thestartup reactor R_s, the ammonia tank, and/or any valves or other flowcontrol units for controlling a flow of various fluids or materialsbetween the components of the ammonia powerpack system. The battery unitmay be coupled to a portion of the fuel cell unit.

In some cases, the ammonia powerpack system may comprise a heatexchanger and/or an adsorbent tower as described elsewhere herein. Theheat exchanger and the adsorbent tower may be in fluid communicationwith the main reactor R_m. The heat exchanger and the adsorbent towermay be coupled to or positioned adjacent to a portion of the fuel cellunit. In some embodiments, the heat exchanger and the adsorbent towermay be positioned on a first side of the fuel cell unit. In some cases,the main reactor R_m may be positioned on a second side of the fuel cellunit, the startup reactor R_s may be positioned on a third side of thefuel cell unit, and the battery unit may be positioned on a fourth sideof the fuel cell unit. The ammonia tank may be positioned on a fifthside of the fuel cell unit. The ammonia powerpack configuration shown inFIG. 26 may be utilized for a compact system (e.g., a system with powerrequirements less than about 100 kilowatts).

As shown in FIG. 27 , in some cases the ammonia powerpack system may beadapted for a larger system (e.g., a system with power requirementsexceeding 100 kilowatts). The ammonia powerpack system may comprise anammonia tank, a heat exchanger, a startup reactor R_s, a main reactorR_m, one or more adsorption towers, a fuel cell unit, and a batteryunit. The heat exchanger, the startup reactor R_s, the main reactor R_m,the one or more adsorption towers, the fuel cell unit, and the batteryunit may be positioned adjacent to the ammonia tank. The ammonia tankmay be in fluid communication with the heat exchanger. Ammonia from theammonia tank may flow through the heat exchanger and into the startupreactor R_s for processing. Hydrogen and/or nitrogen produced from thedecomposition of ammonia may be directed from the startup reactor to themain reactor. The hydrogen extracted from the ammonia by the startupreactor may be combusted in the main reactor for heating of the mainreactor. In some cases, ammonia from the ammonia tank and/or unconvertedammonia from the startup reactor may be directed to the main reactor R_mfor ammonia cracking or decomposition. Once the ammonia is cracked usingthe main reactor R_m, products including hydrogen and nitrogen may bedirected from the main reactor to the heat exchanger to cool the exitflow before the hydrogen and/or nitrogen of the exit flow is directed toone or more adsorbent towers. In some cases, the exit flow may compriseunconverted ammonia in addition to the hydrogen and/or nitrogen. In suchcases, the exit flow may be directed to a first adsorbent tower during afirst time period, and to a second adsorbent tower during a second timeperiod, to remove the unconverted ammonia. The first time period maycorrespond to a time during which the second adsorbent tower is beingregenerated. The second time period may correspond to a time duringwhich the first adsorbent tower is being regenerated. The adsorbenttowers may be used to remove any excess ammonia before the exit flowcomprising hydrogen and/or nitrogen is directed to the fuel cell unit.The fuel cell unit may be configured to use the hydrogen to generateelectrical energy. In some cases, unconverted hydrogen may be directedback to the main reactor R_m for combustion heating to heat the mainreactor.

FIG. 28 schematically illustrates an ammonia powerpack system that maybe adapted for use on an aerial vehicle. The aerial vehicle maycomprise, for example, a manned aerial vehicle, an unmanned aerialvehicle, an aircraft, an airplane, a helicopter, or a drone. Theconfiguration of the ammonia powerpack system shown in FIG. 28 may besimilar to the configuration shown in FIG. 26 . In some cases, theammonia power pack system may be integrated into a body of the aerialvehicle. In other cases, the ammonia power pack system may be placed ontop of or underneath a body of the aerial vehicle.

FIG. 29 schematically illustrates another example of an ammoniapowerpack system that may be adapted for use on an aerial vehicle. Theammonia powerpack system may comprise an ammonia tank, one or more fuelcell units, a battery unit, a startup reactor R_s, a main reactor R_m, aheat exchanger, and an adsorbent tower. The one or more fuel cell units,the battery unit, the startup reactor R_s, the main reactor R_m, theheat exchanger, and the adsorbent tower may be positioned around theammonia tank. The ammonia powerpack system may be placed on top of orunderneath a portion of the aerial vehicle. Alternatively, the ammoniapowerpack system may be integrated with a structural portion or acomponent of the aerial vehicle.

FIG. 30 schematically illustrates an example of an ammonia powerpacksystem that may be adapted for use on a terrestrial vehicle, such as acar or an automobile. The ammonia powerpack system may comprise one ormore fuel cells, one or more adsorbent towers, a startup reactor R_sand/or a main reactor R_m, a heat exchanger, a battery unit, and anammonia tank. The one or more fuel cells may be placed in or near afront portion of the vehicle (e.g., in an engine bay of the vehicle).The adsorbent towers, the startup reactor R_s, the main reactor R_m, andthe heat exchanger may be placed in or near an underside region of thevehicle. The ammonia tank may be placed near a rear end of the vehicle.The battery unit may be positioned between the ammonia tank and theother components of the ammonia powerpack system.

FIG. 31 schematically illustrates another example of an ammoniapowerpack system that may be adapted for use on a terrestrial vehicle,such as a car or an automobile. The ammonia powerpack system maycomprise one or more fuel cells, one or more adsorbent towers, a startupreactor R_s and/or a main reactor R_m, a heat exchanger, a battery unit,and an ammonia tank. The one or more fuel cells and the one or moreadsorbent towers may be placed in or near an underside region of thevehicle. The ammonia tank and the battery unit may be placed near anaxle of the vehicle (e.g., a rear wheel axle of the vehicle). Thestartup reactor R_s, the main reactor R_m, and the heat exchanger may beplaced in or near a front portion of the vehicle (e.g., in an engine bayof the vehicle).

FIGS. 32 - 35 schematically illustrate examples of an ammonia powerpacksystem that may be adapted for use on a terrestrial vehicle, such as atruck or a semi-trailer truck. The ammonia powerpack system may compriseone or more fuel cells, one or more adsorbent towers, one or morestartup reactors, one or more main reactors, one or more heatexchangers, one or more battery units, and/or one or more ammonia tanks.

In some cases, the one or more ammonia tanks may be coupled to orintegrated into a rear portion of a tractor unit of the truck. Thetractor unit (also known as a prime mover, truck, semi-truck,semi-tractor, rig, big rig, or simply, a tractor) may comprise aheavy-duty towing engine that provides motive power for hauling a towedor trailered-load. As shown in FIG. 32 , in some cases, the one or morefuel cell units may be positioned in or near a front portion of thetractor unit (e.g., in the engine bay of the tractor unit). In suchcases, the one or more adsorbent towers, the one or more startupreactors, the one or more main reactors, the one or more heatexchangers, and the one or more battery units may be placed in or nearan underside region of the tractor unit. In other cases, for example asshown in FIG. 33 , the one or more startup reactors and the one or moremain reactors may be positioned in or near a front portion of thetractor unit (e.g., in the engine bay of the tractor unit). In suchcases, the one or more adsorbent towers, the one or more heatexchangers, the one or more battery units, and the one or more fuel cellunits may be placed in or near an underside region of the tractor unit.

FIG. 34 schematically illustrates an example of an ammonia powerpacksystem that may be adapted for use on a terrestrial vehicle, such as atruck or a semi-trailer truck. In some instances, as shown in FIG. 34 ,the ammonia powerpack system may comprise a plurality of powerpackmodules. The plurality of powerpack modules may comprise at least onepowerpack comprising a main reactor R_m, a startup reactor R_s, and aheat exchanger. The plurality of powerpack modules may be positioned inor near an underside region of the tractor unit. The plurality ofpowerpack modules may be distributed along the underside of the tractorunit. In some cases, the one or more fuel cells may be positioned in ornear a front portion of the tractor unit (e.g., in the engine bay of thetractor unit). In some cases, the one or more adsorbent towers and theone or more battery units may be positioned between the one or more fuelcells and the plurality of powerpack modules.

FIG. 35 schematically illustrates another example of an ammoniapowerpack system that may be adapted for use on a terrestrial vehicle,such as a truck or a semi-trailer truck. As shown in FIG. 35 , theammonia powerpack system may comprise a plurality of powerpack modules.The plurality of powerpack modules may comprise at least one powerpackcomprising a main reactor R_m, a startup reactor R_s, and a heatexchanger. The plurality of powerpack modules may be positioned in ornear a front portion of the tractor unit (e.g., in the engine bay of thetractor unit). In some cases, one or more of the powerpack modules maybe positioned near an axle (e.g., a front axle) of the tractor unit. Insome cases, one or more of the powerpack modules may be positioned in ornear an underside region of the tractor unit. In some cases, the one ormore fuel cells, the one or more battery units, and/or the one or moreadsorbent towers may be positioned in or near an underside of thetractor unit. In some cases, the one or more adsorbent towers and theone or more battery units may be positioned between the one or more fuelcells and the plurality of powerpack modules.

In some cases, the plurality of powerpack modules may be positionedadjacent to each other. In other cases, the plurality of powerpackmodules may be located remote from each other (i.e., in or on differentsides, regions, or sections of a vehicle). In some cases, the pluralityof powerpack modules may be oriented in a same direction. In othercases, at least two of the plurality of powerpack modules may beoriented in different directions. In any of the embodiments describedherein, the plurality of powerpack modules may be positioned and/ororiented appropriately to maximize volumetric efficiency and minimize aphysical footprint of the plurality of powerpack modules. In any of theembodiments described herein, the plurality of powerpack modules may bepositioned and/or oriented to conform with a size and/or a shape of thevehicle in or on which the powerpack modules are positioned or provided.In any of the embodiments described herein, the plurality of powerpackmodules may be positioned and/or oriented to conform with a size and/ora shape of the vehicle to which the powerpack modules are coupled ormounted.

In any of the embodiments described herein, the components of thepowerpacks disclosed herein may be positioned in or on different sides,regions, or sections of a vehicle. In some cases, a first subset of thepowerpack components may be positioned remotely from a second subset ofthe powerpack components. The components of the powerpack system may bepositioned and/or oriented appropriately to maximize volumetricefficiency and minimize a physical footprint of the powerpack system.The components of the powerpack system may be positioned and/or orientedto conform with a size and/or a shape of the vehicle in or on which thepowerpack system is positioned or provided. The components of thepowerpack system may be positioned and/or oriented to conform with asize and/or a shape of the vehicle to which the powerpack system iscoupled or mounted.

FIG. 80A shows a powerpack, in accordance with one or more embodimentsof the present disclosure. In some cases, a powerpack comprising areformer and a fuel cell may be mounted on the tractor. FIG. 80Bschematically illustrates a tractor having a mounted powerpack, inaccordance with one or more embodiments of the present disclosure. Insome cases, a powerpack comprising a reformer and a fuel cell may bemounted within a chassis of a tractor. In some cases, a powerpackcomprising a reformer and a fuel cell may be positioned in a hood or aboot of a tractor. In some cases, the components of the powerpack may bemounted to or integrated with various portions or structural componentsof the tractor. The components may be mounted to different regions orportions of the tractor to optimize weight balance and/or center ofgravity. In some cases, one or more auxiliary batteries may supporttractor power demand and/or may power a startup process. In some cases,an ammonia storage tank may be positioned on a rear side of the vehicle.In some cases, fuel cell heat rejection via a heat exchanger (orradiator) may be used to evaporate the liquid ammonia fuel beforeentering a reactor.

In another aspect, the present disclosure provides a system fordecomposing ammonia to generate hydrogen. The system may comprise one ormore reactors and one or more combustors for heating the one or morereactors, as described in greater detail below. FIGS. 36A-36Cschematically illustrates some exemplary systems for decomposingammonia, in accordance with one or more embodiments of the presentdisclosure.

The system may comprise any number of the various components disclosedherein. In some cases, the system may comprise an ammonia tank. In somecases, the system may comprise a reactor. In some cases, the reactor maybe in fluid communication with the ammonia tank. In some cases, thesystem may comprise one or more adsorbents. In some cases, the systemmay comprise one or more fuel cells.

The reactor may comprise any number of reactor structures or reactorconfigurations disclosed herein, and may be configured to perform anynumber of the various functions of reactors disclosed herein. In somecases, the reactor may be configured to decompose ammonia received fromthe ammonia tank to generate a reactor exit flow comprising at leasthydrogen.

In some cases, the reactor exit flow further may comprise undecomposedammonia. In some cases, the reactor exit flow further may comprisenitrogen.

The reactor exit flow may comprise various flow rates. In some cases,the reactor exit flow may comprise a flow rate of at least about 10liters per minute (e.g., at standard temperature and pressure) to atmost about 20 liters per minute. In some cases, the reactor exit flowmay comprise a flow rate of at least about 0.1 liters per minute (lpm)to at most about 100 lpm. In some cases, the reactor exit flow maycomprise at least about 10 lpm to at most about 500 lpm. In some cases,the reactor exit flow may comprise at least about 100 lpm to at mostabout 1000 lpm. In some cases, the reactor exit flow may comprise atleast about 500 lpm to at most about 10,000 lpm.

The reactor exit flow may comprise various temperatures. In some cases,the reactor exit flow may comprise a temperature of at least about 100,200, 300, 400, 500, or 600° C. In some cases, the reactor exit flow maycomprise a temperature of at most about 100, 200, 300, 400, 500, or 600°C. In some cases, the reactor exit flow may comprise a temperature of atleast about 20° C. to at most about 1000° C. In some cases, the reactorexit flow may comprise a temperature of at least about 100° C. to atmost about 500° C.

The reactor exit flow may comprise various pressures. In some cases, thereactor exit flow may comprise a pressure of at least about 1 bar to atmost about 5 bar. In some cases, the reactor exit flow may comprise apressure of at least about 0.1 bar (gauge) to at most about 20 bar(gauge). In some cases, the reactor exit flow may comprise a pressure ofat least about 1 bar (gauge) to at most about 100 bar (gauge).

Hydrogen may comprise various fractions of the reactor exit flow. Insome cases, hydrogen may comprise at least about 0.1 mole fraction to atmost about 0.75 mole fraction of the reactor exit flow.

Undecomposed ammonia may comprise various fractions of the reactor exitflow. In some cases, undecomposed ammonia may comprise at most about 0.9mole fraction ammonia of the reactor exit flow. In some cases,undecomposed ammonia may comprise at most about 0.05 mole fractionammonia of the reactor exit flow. In some cases, undecomposed ammoniamay comprise at most about 0.005 mole fraction ammonia of the reactorexit flow. In some cases, undecomposed ammonia may comprise at mostabout 0.0005 mole fraction ammonia of the reactor exit flow.

Nitrogen may comprise various fractions of the reactor exit flow. Insome cases, nitrogen may comprise at least about 0.05 mole fraction toat most about 0.25 mole fraction of the reactor exit flow.

The one or more adsorbents may comprise any number of adsorbentstructures or adsorbent configurations disclosed herein, and may beconfigured to perform any number of the various functions of adsorbentsdisclosed herein. In some cases, the one or more adsorbents may beconfigured to filter out or remove unconverted ammonia from at least aportion of the reactor exit flow to provide a filtered reactor exitflow.

The one or more adsorbents may be configured to filter out or removevarious fractions of the unconverted ammonia from at least a portion ofthe reactor exit flow. In some cases, the one or more adsorbents may beconfigured to filter out or remove at least about 10 ppm to at mostabout 100,000 ppm of the unconverted ammonia. In some cases, the one ormore adsorbents may be configured to produce filtered product streamwith less than 10 ppm of ammonia.

The one or more adsorbents may be configured to filter out or removevarious portions of the reactor exit flow. In some cases, the one ormore adsorbents may be configured to filter out or remove at least about10 ppm to at most about 100,000 ppm ammonia of the reactor exit flow. Insome cases, the one or more adsorbents may be configured to filter outor remove at least about 10 ppm to at most about 500,000 ppm ammonia ofthe reactor exit flow.

The filtered reactor exit flow may comprise various flow rates. In somecases, the filtered reactor exit flow may comprise a flow rate of atleast about 10 lpm (standard temperature and pressure) to at most about20 lpm. In some cases, the filtered reactor exit flow may comprise aflow rate of at least about 0.1 liters per minute (lpm) to at most about100 lpm. In some cases, the filter reactor exit flow may comprise a flowrate of at least about 100 lpm to at most about 500 lpm. In some cases,the filter reactor exit flow may comprise a flow rate of at least about200 lpm to at most about 1000 lpm.

The filtered reactor exit flow may comprise various temperatures. Insome cases, the filtered reactor exit flow may comprise a temperature ofat least about 100, 200, 300, 400, 500, or 600° C. In some cases, thefiltered reactor exit flow may comprise a temperature of at most about100, 200, 300, 400, 500, or 600° C. In some cases, the filtered reactorexit flow may comprise a temperature of at least about 20° C. to at mostabout 1000° C. In some cases, the filtered reactor exit flow maycomprise a temperature of at least about 100° C. to at most about 500°C.

The filtered reactor exit flow may comprise various pressures. In somecases, the filtered reactor exit flow may comprise a pressure of atleast about 0.1 bar (gauge) to at most about 100 bar.

Hydrogen may comprise various fractions of the filtered reactor exitflow. In some cases, hydrogen may comprise at least about 0.1 molefraction to at most about 0.75 mole fraction of the filtered reactorexit flow.

Undecomposed ammonia may comprise various fractions of the filteredreactor exit flow. In some cases, the filtered reactor exit flow maycomprise at most about 100 ppm ammonia. In some cases, the filteredreactor exit flow may comprise at most about 10 ppm ammonia. In somecases, the filtered reactor exit flow may comprise at most about 1 ppmammonia. In some cases, the filtered reactor exit flow may comprise atleast about 0.1 ppm ammonia to at most about 1000 ppm ammonia. In somecases, the filtered reactor exit flow may comprise less than 0.1 ppmammonia.

Nitrogen may comprise various fractions of the filtered reactor exitflow. In some cases, nitrogen may comprise at least about 0.05 molefraction to at most about 0.25 mole fraction of the filtered reactorexit flow.

In some cases, the one or more fuel cells may be in fluid communicationwith the reactor. In some cases, the one or more fuel cells may be influid communication with the one or more adsorbents. In some cases, theone or more fuel cells may be configured to receive the filtered reactorexit flow from the one or more adsorbents. In some cases, the one ormore fuel cells may be configured to process the filtered reactor exitflow to generate electricity. In some cases, the one or more fuel cellsmay be configured to output a fuel cell exit flow comprising unconvertedhydrogen. In some cases, the fuel cell exit flow may further comprisehydrogen. In some cases, the fuel cell exit flow may further comprisenitrogen.

The one or more fuel cells may generate various amounts of electricity.In some cases, the one or more fuel cells may generate at least about400 W to at most about 600 W of electricity. In some cases, the one ormore fuel cells may generate at least about 10 W to at most about 1 MWof electricity. In some cases, the one or more fuel cells may generateat least about 100 kW to at most about 1000 kW of electricity. In somecases, the one or more fuel cells may generate at least about 1 MW to atmost about 10 MW of electricity.

The fuel cell exit flow may comprise various flow rates. In some cases,the fuel cell exit flow may comprise a temperature of at least about100, 200, 300, 400, 500, or 600° C. In some cases, the fuel cell exitflow may comprise a temperature of at most about 100, 200, 300, 400,500, or 600° C. In some cases, the fuel cell exit flow may comprise atemperature of at least about 20° C. to at most about 1000° C. In somecases, the fuel cell exit flow may comprise a temperature of at leastabout 100° C. to at most about 500° C.

The fuel cell exit flow may comprise various pressures. In some cases,the fuel cell exit flow may comprise a pressure of at least about 0.01bar (gauge) to at most about 10 bar (gauge).

Hydrogen may comprise various fractions of the fuel cell exit flow. Insome cases, hydrogen may comprise at least about 0.01 mole fraction toat most about 0.75 mole fraction of the fuel cell exit flow.

Undecomposed ammonia may comprise various fractions of the fuel cellexit flow. In some cases, undecomposed ammonia may comprise at leastabout 1 ppm to at most about 100 ppm of the fuel cell exit flow. In somecases, undecomposed ammonia may comprise at least about 0.01 ppm to atmost about 1 ppm of the fuel cell exit flow

Nitrogen may comprise various fractions of the fuel cell exit flow. Insome cases, nitrogen may comprise at least about 0.25 mole fraction toat most about 1 mole fraction of the fuel cell exit flow.

Combustor Designs

In some cases, the one or more combustors may be in fluid communicationwith the ammonia tank. In some cases, the one or more combustors may bein fluid communication with the reactor. In some cases, the one or morecombustors may be in fluid communication with the one or moreadsorbents. In some cases, the one or more combustors may be in fluidcommunication with the one or more fuel cells. In some cases, the one ormore combustors may be in fluid communication with the ammonia tank, thereactor, the one or more adsorbent, the one or more fuel cells, or anycombination thereof.

In some cases, the one or more combustors may be configured to combustat least a portion of the reactor exit flow to generate thermal energyfor heating the reactor and/or a catalyst material within the reactor,as shown in FIG. 36A. In some cases, the one or more combustors may beconfigured to combust at least a portion of the filtered reactor exitflow to generate thermal energy for heating the reactor, as shown inFIG. 36B. In some cases, the one or more combustors may be configured tocombust at least a portion of the fuel cell exit flow to generatethermal energy for heating the reactor, as shown in FIG. 36C. In somecases, the one or more combustors may be configured to combust at leasta portion of the reactor exit flow to heat the plurality of differentregions within the reactor. In some cases, the one or more combustorsmay be configured to combust at least a portion of the fuel cell exitflow to heat the plurality of different regions within the reactor.

Various portions of the reactor exit flow may be combusted by the one ormore combustors. In some cases, at least about 5% to at most about 50%of the hydrogen from the reactor exit flow may be combusted by the oneor more combustors.

Various portions of the filtered reactor exit flow may be combusted bythe one or more combustors. In some cases, at least about 5% to at mostabout 50% of the hydrogen from the filtered reactor exit flow may becombusted by the one or more combustors.

Various portions of the fuel cell exit flow may be combusted by the oneor more combustors. In some cases, at least about 10% to at most about100% of the hydrogen from the fuel cell exit flow may be combusted bythe one or more combustors.

In some cases, the system may further comprise an air supply unit. Insome cases, the air supply unit may be in fluid communication with theone or more combustors. In some cases, the air supply unit may beconfigured to supply at least oxygen to the one or more combustors. Insome cases, the air supply unit may be configured to supply air from theatmosphere to the one or more combustors.

The air supply unit may supply oxygen to the one or more combustors atvarious flow rates. In some cases, the air supply unit may supply oxygenat a flow rate of at least about 10 lpm to at most about 100 lpm. Insome cases, the air supply unit may supply oxygen at a flow rate of atleast about 100 lpm to at most about 1000 lpm.

The air supply unit may supply oxygen to the one or more combustors atvarious pressures. In some cases, the air supply unit may supply oxygenat a pressure of at least about 0.1 bar (gauge) to at most about 20 bar(gauge).

In some cases, the air supply unit may comprise a fan or a blower, asshown in FIG. 37A. In some cases, the air supply unit may comprise acompressor, as shown in FIG. 37B, to provide pressured air from theatmosphere. In some cases, the air supply unit may comprise a turbine,as shown in FIG. 37B. In some cases, the air supply unit may comprise aturbocharging unit, as shown in FIG. 37B. In some cases, the air supplyunit may comprise a compressed cylinder. In such cases, the air supplyunit may be configured to provide pressurized air from the cylinder tothe one or more combustors. In some cases, the air supply unit maycomprise a venturi restriction. The venturi restriction may be used tocreate a differential pressure between the venturi restrictions andanother region of the air supply unit. The differential pressure may beused to draw air from the atmosphere into the venturi restriction.

In some cases, the one or more combustors may comprise an atmosphericcombustor as shown in FIG. 37C. In some cases, the atmospheric combustormay be configured to receive a supply of air or oxygen from a compressedcylinder or a fan blower.

In some cases, the one or more combustors may comprise a naturallyaspirated combustor. In some cases, the naturally aspirated combustormay be configured to receive a supply of air or oxygen from an ambientenvironment in part based on a vacuum induced within the combustor.

In some cases, the one or more combustors may comprise a pressurizedcombustor. In some cases, the pressurized combustor may be configured toreceive a supply of air or oxygen from a compressor coupled to aturbine. In some cases, the turbine may be driven by one or more exhaustgases from the pressurized combustor.

As described elsewhere herein, the system may comprise one or morecombustors. In some cases, the one or more combustors may be embedded atleast partially within the reactor, as shown in FIGS. 38A-38B, FIG. 39 ,FIGS. 40A-40D, FIG. 42 . In some cases, the one or more combustors maybe configured to generate thermal energy for heating the reactor in aplurality of different regions to facilitate ammonia decomposition, asshown in FIG. 42 . Various portions of the one or more combustors may beembedded in the reactor. The one or more combustors may be embedded invarious regions of the reactor so that various regions within thereactor may be separately and/or individually heated by the one or morecombustors.

In some cases, the one or more combustors may be configured to combust amixture of air and fuel that may be at least partially pre-mixedupstream of a combustion region, as shown in FIG. 38A. In some cases,premixing the mixture of air and fuel allows for a more completecombustion of the air-fuel mixture at the combustion zone.

In some cases, the one or more combustors may be configured to combust amixture of air and fuel, wherein the air and the fuel may be mixed at ornear the combustion region, as shown in FIG. 38B.

The fuel may be sourced from one or more of the various componentsdisclosed herein. In some cases, the fuel may comprise the reactor exitflow. In some cases, the fuel may comprise the filtered reactor exitflow. In some cases, the fuel may comprise the fuel cell exit flow. Insome cases, the fuel may comprise an ammonia flow from the ammoniastorage tank. In some cases, the fuel may comprise hydrogen, nitrogen,and ammonia.

In some cases, the one or more combustors may comprise one or moreair-fuel contact zones configured to mix a flow comprising hydrogen anda flow comprising oxygen to facilitate combustion. FIG. 39 shows anillustration of one embodiment of the system comprising two air-fuelcontact zones with one combustor. The two air-fuel contact zones may belocated at a pre-determined distance upstream from the combustion zone.In some cases, the two air-fuel contact zones may comprise an auxiliarycontact zone and a main contact zone. In some cases, the auxiliarycontact zone and the main contact zone may be separated by apredetermined distance. In some cases, the predetermined distance may beat least about 1 mm to about 1 meter. In some cases, the predetermineddistance may be at least about 1 cm to about 20 cm.

The one or more combustors may comprise any number of combustion zonesat various locations within the reactor. In some cases, the one or morecombustors may comprise 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 combustionzones.

The one or more combustors may comprise any number of air-fuel contactzones at various locations within the reactor. In some cases, the one ormore combustors may comprise 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 air-fuelcontact zones.

The one or more combustors may comprise any number of air-fuelpre-mixing zones at various locations within the reactor. In some cases,the one or more combustors may comprise 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10air-fuel pre-mixing zones.

In some cases, a hydrogen and nitrogen supply tube and a combustor endmay be separated by various distances. FIGS. 40A-40D show illustrationsof one embodiment of the system comprising a combustor configured forcombustion inside a reactor. FIG. 40C illustrates some dimensions of asystem comprising a combustor configured for combustion inside areactor, including: distance between the air supply tube and the reactorend (4001), distance between the H₂/N₂ mixture supply tube and thereactor end (4002), combustor insertion length into the reactor (4003),and reactor length (4004). FIG. 40D shows a photograph of one embodimentof the system comprising a combustor configured for combustion inside areactor.

Experiments were carried out to assess system performance while varyingNH₃ flow rates and the positions of the hydrogen and nitrogen mixture(1:1 volume ratio) supply tube and air supply tube relative to acombustor end configured for combustion. The results of theseexperiments are shown in FIGS. 41A-41B. Improvements in the reactor andcombustor efficiencies were observed by adjusting the positions of thehydrogen and nitrogen mixture supply tube and air supply tube relativeto the combustor end. FIG. 41A shows the reactor thermal reformingefficiency as a function of ammonia flow rate and FIG. 41B shows thecombustor efficiency as a function of ammonia flow rate. In thisexample, reactor thermal reforming efficiency is defined as (chemicalenergy of produced hydrogen) / (chemical energy of input ammonia + heatenergy input), i.e., lower heating value of produced hydrogen relativeto the sum of lower heating value of input ammonia and heat energyinput. In this example, heat energy input accounts for the heat ofreaction and heat loss. In this example, the combustor efficiency isdefined as (hydrogen enthalpy of combustion - enthalpy of combustor exitflow)/(hydrogen enthalpy of combustion). For instance, Air 2 cm - H2/N₂12 cm - Insertion Length 30 cm refers to distance between the air supplytube and the combustor end of 2 cm (i.e., 4001 in FIG. 40C), distancebetween the hydrogen and nitrogen mixture supply tube and the combustorend of 12 cm (i.e., 4002 in FIG. 40C), and the combustor insertionlength inside the reactor of 30 cm (the combustor length is about 30 cmfrom the end to the exhaust outlet, therefore, 30 cm insertion lengthrefers to the complete insertion, i.e., 4003 in FIG. 40C).

In some cases, the one or more combustors may comprise two or morecombustors configured to heat a plurality of different regions withinthe reactor. The plurality of different regions may correspond todistinct combustion zones. FIG. 42 shows an illustration of oneembodiment of the system comprising two combustors. The two combustorsmay be cylindrical and may be concentrically embedded in the reactor,which may also be cylindrical. The two combustors may be diametricallyopposed with a separation distance between opposing faces of thecombustors. The combustors may be configured to separately orindependently heat at least two different regions within the reactor.

The air and the fuel may be mixed and combusted at various distancesaway from a combustor end. FIGS. 43-45 each illustrate simulationresults that show the effects of mixing and combustion of the air andthe fuel at various distances. In each simulation, cylindrical tubes areconcentrically embedded in a cylindrical combustor. Combustion takesplace at the air-fuel mix location, and the heated flow is turned aroundat the end of the combustor and transported in a direction opposite theair/fuel supply direction. As mixing the fuel and air is required forcomplete combustion, not all of hydrogen is combusted at the air-fuelmixing location immediately but the flame stretches through thecombustor with the flow of the air-fuel mixture. This heat may be thentransferred to the most outer wall of the combustor and to the externalsurroundings (e.g., reactor). The air-fuel contact and combustion zonemay be located at a pre-determined distance from the combustor end, forinstance, about 4 cm in FIG. 43 , about 2 cm in FIG. 44 , about 6 cm inFIG. 45A, and about 8 cm in FIG. 45B. In each simulation, the fuel(H₂/N₂ 1:1 volume ratio mixture) flow rate was 10 lpm, and the air flowrate was 20 lpm. The temperature profile within the system was computedunder steady-state assumptions for each simulation. With eachconfiguration in FIGS. 43-45 , the temperature profiles varied withrespect to the maximum temperature within the combustor, which mayimpact the stability of materials in the system. In some cases, thetemperature profiles also varied with respect to the maximum temperaturegradient within the reactor, which may induce different levels of stressand/or oxidation in the materials in the system. In some cases, thetemperature profiles also varied with respect to the distribution oftemperature at various regions in the combustor, which may impact theperformance of the reactor.

FIGS. 46A-46B each illustrate simulation results that show the effectsof pre-mixing/pre-combustion holes for the air and the fuel at variousdistances. At the pre-mixing/pre-combustion holes, fuel and air may bemixed partially and combusted. This mechanism may distribute the heatmore uniformly throughout the combustor and may reduce local hot spottemperatures, in comparison to cases without pre-mixing/precombustionholes. For example, FIG. 46A shows a temperature distribution whereinthe case with no pre-mixing/pre-combustion holes has the highest localhot spot temperatures in comparison to the cases with holes (e.g., 1, 2,and 3 holes). Thus, pre-mixing/pre-combustion holes may impact thestability of materials in the system. The maximum temperature gradientwithin the reactor also varied between the cases, wherein the variousmaximum temperature gradient may induce different levels of stress andoxidation in the materials of the system. In some cases, the temperatureprofiles also varied in the distribution of temperature at variousregions in the combustor, which may impact the performance of thereactor.

The one or more combustors may each comprise various shapes and sizes.In some cases, the one or more combustors may comprise a cylindricalshape or a circular cross-section, as shown in FIGS. 40A-40D, and FIGS.43-45B. In some cases, the one or more combustors may comprise arectangular shape or a rectangular cross-section. In some cases, the oneor more combustors may be concentric to the reactor.

In some cases, the one or more combustors may comprise a hightemperature refractory material. High temperature refractory materialsmay be resistant to thermal shock, be chemically inert, have specificranges of thermal conductivity, or have specific ranges of thermalexpansion coefficient. In some cases, the high temperature refractorymaterial may be configured to enhance combustor stability. In somecases, the temperature refractory material may comprise steel, tungstencarbide alumina, magnesia, silica, lime, metal oxides, tungsten,molybdenum, or any combination thereof. In some cases, the temperaturerefractory material may comprise at least one of: metal oxides such asAl₂O₃, SiO₂, ZrO₂, VO₂, Ta, alloys of Ni, Al, Mo, Cr, Si, or anycombination thereof. In some cases, the temperature refractory materialmay comprise at least one of steel, tungsten, molybdenum, tungstencarbide, or any combination thereof. In some cases, the refractorymaterial may be coated on one or more surfaces of the one or morecombustors. The refractory material may be coated on or near thecombustion zone, on or near the surfaces that contact the reactor, orany other surface of the reactor. In some cases, the refractory materialmay be enforced with a structural metal. In some cases, the refractorymaterial may be held and/or covered by a structural metal such that thestructural metal supports the refractory material against one or morefractures.

FIGS. 47-48 each schematically illustrates a design for a combustor anda reactor, in accordance with one or more embodiments of the presentdisclosure. In some cases, the combustor and the reactor may comprisedimensions such that the combustor may fit within the reactor.

The reactor may be configured to receive ammonia from a tank and toprocess the ammonia (as described elsewhere herein) to generate hydrogenand/or nitrogen. Processing the ammonia may comprise cracking,decomposing or dissociating the ammonia to yield the hydrogen and/or thenitrogen. The hydrogen and/or nitrogen may flow out from the reactor toone or more adsorbents before the mixture of hydrogen and nitrogen isdirected to one or more fuel cells. The adsorbents may be used to removetrace ammonia and/or nitrogen from the outlet flow of the reactor. Theone or more fuel cells may be configured to generate electrical energyfrom the hydrogen/nitrogen mixture. In some cases, the one or more fuelcells may have an exhaust flow comprising unconverted or unprocessedhydrogen and/or nitrogen.

In some cases, the reactor may comprise a combustor that is positionedat least partially within the reactor. The combustor may be configuredto receive air through a first inlet and a mixture of hydrogen andnitrogen from the one or more fuel cells through a second inlet. Thecombustor may comprise an inner region or volume for combusting themixture of hydrogen and nitrogen with supplied air to heat the reactorfor further ammonia decomposition.

The combustor may comprise various sizes and various cross-sectionalareas. In some cases, a combustor having a larger cross-sectional area,e.g. FIG. 47 , may experience a lower pressure drop than a combustorhaving a smaller cross-sectional area, e.g. FIG. 48 . In some cases, acombustor may have a cross-sectional area between 5 cm² and 25 cm². Insome cases, a combustor may have a cross-sectional area between 25 cm²and 200 cm². In some cases, a combustor may have a cross-sectional areabetween 10 cm² and 500 cm². In some cases, a combustor may have across-sectional area between 100 cm² and 5000 cm².

The combustor may comprise one or more inlets and one or more outlets atvarious locations on the combustor. In some cases, the combustor maycomprise one or more inlets and one or more outlets on a same side ofthe combustor. In some cases, the combustor may comprise one or moreinlets and one or more outlets on different sides of the combustor.

The combustor may comprise one or more inlets and one or more outletsoriented in various directions on the combustor. In some cases, thecombustor may comprise one or more inlets and one or more outletsoriented in a same direction. In some cases, the combustor may compriseone or more inlets and one or more outlets oriented in perpendiculardirections. In some cases, the combustor may comprise one or more inletsand one or more outlets oriented along the longest axis of thecombustor. In some cases, the combustor may comprise one or more inletsand one or more outlets oriented perpendicular to the longest axis ofthe combustor. In some cases, the combustor may comprise one or moreinlets and one or more outlets oriented in a single direction. In somecases, the combustor may comprise one or more inlets and one or moreoutlets oriented in at least two different directions. In some cases,the combustor may comprise one or more inlets and one or more outletsoriented in at least three different directions.

The systems disclosed herein may comprise a mobile system with variousvolumes. In some cases, the mobile system may have a volume of at mostabout 10 m³. In some cases, the mobile system may have a volume of atmost about 2 m³. In some cases, the mobile system may have a volume ofat most about 1 m³. In some cases, the mobile system may have a volumeof at most about 0.5 m³. In some cases, the mobile system may have avolume of at most about 0.25 m³. In some cases, the mobile system mayhave a volume of at most about 0.1 m³. In some cases, the mobile systemmay have a volume of at most about 0.05 m³. In some cases, the mobilesystem may have a volume of at most about 0.01 m³.

In some embodiments, the system may comprise a plurality of reactorsconnected in parallel. In some cases, the plurality of reactors maycomprise one or more combustor reactors and one or more electricalreactors (e.g., 4 or more electrical reactors). In some cases, a heatexchanger may be used to transfer heat and/or evaporate incoming ammoniaflow from one or more exit flows from the one or more combustor reactorsor electrical reactors. In some cases, after the heat exchanger,preheated ammonia stream may be distributed evenly between each reactorin the plurality of reactors. In some cases, flow distribution in one ormore reactors in the plurality reactors may be enhanced using a pressuredrop element, such as a restrictive orifice. In some cases, adistributed preheated and/or evaporated ammonia gas may be passedthrough a combustion heater to pre-heat before entering an electricalreactor or a combustion reactor. In some cases, outflow of an electricalreactor may be input to a combustor reactor. In some cases, an outflowof a combustion reactor may be input to an electrical reactor. In somecases, one or more combustor reactor outlet flows may be merged andinput to the heat exchanger. In some cases, one or more electricalreactor outlet flows may be merged and input to the heat exchanger. Insome cases, cooled product gas from the heat exchanger may be passedthrough an additional heat exchanger to further cool towards ambienttemperature. In some cases, adsorbent may be used to filter unconvertedammonia from the product gas from the combustor reactor, the electricalreactor, the heat exchanger, or any combination thereof. In some cases,filtered N₂/H₂ mixture product stream may be supplied to fuel cells. Insome cases, a hydrogen separation unit (e.g., a pressure swingadsorption (PSA) system or hydrogen permeable membrane system) may beused to produce a product gas with a higher concentration of hydrogencompared a flow of gas input to the separation unit. In some cases,unconverted hydrogen from one or more fuel cells may be distributedevenly through each combustion reactors in the plurality of reactors tobe used as combustion fuel. In some cases, a discharged streamcomprising hydrogen and nitrogen from one or more hydrogen separationunits may be distributed evenly through each combustion reactor in theplurality of reactors to be used as combustion fuel. In some cases, oneor more air supply units may provide air for the one or more combustionreactors in the plurality of reactors. In some cases, the system mayoperate using a self-sustaining auto-thermal reforming process. In somecases, depending on the air flow rates to the one or more combustorreactors, hydrogen utilization, and/or hydrogen consumption rate of theone or more fuel cells, flame flare may be observed in proximity toexhaust ports of the one or more combustor reactors. In some cases,hydrogen combustion required to sustain auto-thermal reforming may beabout 25 - 45 % of produced hydrogen from ammonia cracking. In somecases, hydrogen combustion required to sustain auto-thermal reformingmay be at least about 10, 20, 30, 40, 50, 60, 70, 80, or 90 % ofproduced hydrogen from ammonia cracking. In some cases, hydrogencombustion required to sustain auto-thermal reforming may be at mostabout 10, 20, 30, 40, 50, 60, 70, 80, or 90 % of produced hydrogen fromammonia cracking. In some cases, remaining hydrogen, (e.g., 55 - 75%) ofproduced hydrogen, may be consumed by the one or more fuel cells forgenerating electrical power or supplied as a hydrogen gas on demand. Insome cases, at least about 10, 20, 30, 40, 50, 60, 70, 80, or 90 % ofproduced hydrogen from ammonia cracking may be consumed by the one ormore fuel cells for generating electrical power or supplied as ahydrogen gas on demand. In some cases, at most about 10, 20, 30, 40, 50,60, 70, 80, or 90 % of produced hydrogen from ammonia cracking may beconsumed by the one or more fuel cells for generating electrical poweror supplied as a hydrogen gas on demand. In some cases, a higherpercentage of hydrogen produced from ammonia cracking may be consumedduring a startup operation or heating up phase.

FIG. 74 shows a combustion burner head design, in accordance with one ormore embodiments of the present disclosure. In some cases,hydrogen-nitrogen mixture fuel may be supplied through a fuel inlet andair may be supplied to an air inlet. In some cases, thehydrogen-nitrogen mixture fuel may be distributed into one or moreoutlets/slots (e.g., total 4 outlets/slots). In some cases, at theseoutlets, fuel and air may be injected substantially perpendicular to thedirection of flow (e.g., between about 60 and about 120 degrees). Insome cases, the injection of fuel and air may form a rapidly mixing(e.g., swirl) combustion. In some cases, fuel and air lines forproviding the fuel and air may be sized to have a relatively lowpressure drop (e.g., less than about 1 bar). In some cases, fuel and airlines for providing the fuel and air may be sized to maintain a highinjection velocity. In some cases, the high injection velocity may besufficiently high to reduce or prevent back flow and/or flash back, andmay improve mixing, as compared to a lower injection velocity. In somecases, a plenum type reservoir may be used to further minimize thepressure drop. In some cases, an insertable design may be used tofacilitate maintenance and replacement. In some cases, a burner head maybe inserted or permanently attached to a combustor reactor. In somecases, a burner head may comprise one or more fuel or air injectionslots. In some cases, a burner head may comprise one or more insertableseals for inserting into a combustor reactor. In some cases, a burnerhead may comprise an air or fuel injection slot cross-sectional area of1 to 50 mm². In some cases, a burner head may comprise an air or fuelinjection slot cross-sectional area of 1-20 mm². In some cases, a burnerhead may comprise a fuel injection slot cross-sectional area of 4-15 mm²for fuel input. In some cases, a burner head may comprise an airinjection slot cross-sectional area of 5-18 mm² for air input. In somecases, a burner head may comprise a fuel injection slot cross-sectionalarea of 6-12 mm² for fuel input. In some cases, a burner head maycomprise an air injection slot cross-sectional area of 7-15 mm² for airinput. In some cases, fuel velocities and air velocities at one or moreinjection slots may comprise various speeds. In some cases, fuelvelocity may comprise 10- 200 m/s. In some cases, fuel velocity maycomprise 50-130 m/s. In some cases, air velocity may comprise 30 - 250m/s. In some cases, air velocity may comprise 50-200 m/s. In some cases,air velocity may comprise 70-130 m/s.

An ammonia reforming combustor durability test was performed aninstalled burner head for rapid 10+ consecutive on/off temperaturecycles. Throughout 10+ cycles, ammonia reforming performance remainedconstant with an ammonia conversion efficiency of over 99% and ahydrogen consumption of about 30-40% (with respect to the hydrogenproduced by ammonia decomposition) without using any heat exchangers orrecuperators.

FIGS. 75A-75B show a burner head design, in accordance with one or moreembodiments of the present disclosure. In some cases, a burner head maycomprise an optional ammonia preheating line. In some cases, a burnerhead may comprise one or more slots for inputting fuel and/or air. Insome cases, a burner head may comprise at least about 1, 2, 3, 4, 5, 6,7, 8, 9, 10, 11, or 12 slots for inputting fuel and/or air. In somecases, a burner head may comprise at most about 1, 2, 3, 4, 5, 6, 7, 8,9, 10, 11, or 12 slots for inputting fuel and/or air. In some cases, aburner head may comprise an even number of slots (e.g., 2, 4, 6, 8,10...) for inputting fuel and/or air. In some cases, a burner head maybe configured to provide a swirling flow of gases when the fuel and/orair is input trough the one or more slots. In some cases, the burnerhead may be at least partially enclosed in an insulating material. Insome cases, at least one of ammonia, air, and combustion fuel may bepreheated through a concentric flow tube positioned inside the one ormore combustor tubes by exchanging heat with a combustion product gas.In some cases, pressure drop of an air and/or combustion fuel flowthrough the burner head is less than about 2 bar. In some cases,pressure drop of an air and/or combustion fuel flow through the burnerhead is less than about 1 bar. In some cases, pressure drop of an airand/or combustion fuel flow through the burner head is less than about0.5 bar. Air and/or combustion fuel flow through the burner head is lessthan about 5, 4, 3, 2, 1, 0.5, 0.4, 0.3, 0.2, or 0.1 bar. In some cases,pressure drop of an air and/or combustion fuel flow through the burnerhead is greater than about 0.5 bar. air and/or combustion fuel flowthrough the burner head is less than about 5, 4, 3, 2, 1, 0.5, 0.4, 0.3,0.2, or 0.1 bar.

FIGS. 76A-76B show a burner head design, in accordance with one or moreembodiments of the present disclosure. In some cases, a burner head maybe configured to insert into a combustion reactor. In some cases, acombustion reactor may be configured to insert into a burner head. Insome cases, a burner head and an elongated a combustion reactor maycouple at an end of the elongated combustion reactor.

FIG. 77 shows flow simulations in a combustion tube with a burner head,in accordance with one or more embodiments of the present disclosure.Reaction flow simulations were carried out to investigate combustion andreaction characteristics without ammonia reforming. Heat transferboundary conditions of 900 K and 400 W/m^(2-K)were used. When ammoniareforming is considered in the simulation, the progress variable, thevelocity field, and the temperature field may change. Flow field linesare shown without any solid physical boundaries.

FIG. 78 shows flow simulations in a combustion tube with a burner head,in accordance with one or more embodiments of the present disclosure.Fuel and/or air injection (i) slot size or cross-sectional area, (ii)injection direction or angle, (iii) burner insertion depth, or (iv) gapbetween the slot and the combustion tube may be optimized to alter thecombustion characteristics. FIG. 79 shows flow simulations in acombustion tube with a burner head, in accordance with one or moreembodiments of the present disclosure. In some cases, a burner head maycomprise one or more fuel or air inlets that are configured to provide aswirling flow in a combustion reactor. In some cases, the one or morefuel or air inlets may be positioned substantially radiallysymmetrically on a burner head.

Aerial Vehicle

FIG. 49 schematically illustrates an example of a system architecturalconfiguration for an ammonia processing system that may be mounted toand used compatibly with an aerial vehicle. The aerial vehicle maycomprise an unmanned airborne vehicle (UAV), a drone, a rotor craft, afixed wing, a flapping-wing, a helicopter, an airplane, or a jet. Table1 describes each figure element shown in FIG. 49 .

TABLE 1 Description of figure elements in FIG. 49 Mechanical NH3 Ammoniatank PV Valve P Pressure Sensor R Reactor H Heater or Combustor ADSAdsorbent HX Heat Exchanger F Air Supply Unit Atm Atmosphere V Vent FCFuel Cell BA Battery UAV Load Drone Load

In some cases, the system may comprise one or more reactors (R)configured to partially or fully crack ammonia provided to the one ormore reactors to yield hydrogen, nitrogen, and/or ammonia. In somecases, a system may comprise one or more fuel cells (FC) in fluidcommunication with the one or more reactors. In some cases, the one ormore fuel cells are configured to receive and process the hydrogen fromthe one or more reactors to generate electrical energy. In some cases,the one or more reactors and the one or more fuel cells may beconfigured to be mounted on or to an aerial vehicle. In some cases, theone or more fuel cells are in electrical communication with one or moremotors or drive units of the aerial vehicle to drive the one or moremotors or drive units of the aerial vehicle. The drive units maycomprise, for example, one or more rotors or propellers.

In some cases, the one or more reactors may be configured to be mountedto an aerial vehicle. In some cases, the one or more fuel cells may beconfigured to be mounted to an aerial vehicle. In some cases, the one ormore reactors and the one or more fuel cells may be configured to bemounted to an aerial vehicle. In some cases, the one or more motors ordrive units may be configured to be mounted to an aerial vehicle.

In another aspect, the present disclosure provides an ammonia power packsystem that may be mounted to an aerial vehicle to power one or moremotors or drive units of the aerial vehicle. In some cases, the ammoniapowerpack system may have an optimized physical layout and/or packaging.FIG. 50 shows a digital rendition of an ammonia powerpack system, inaccordance with one or more embodiments of the present disclosure. Thisrendition shows an embodiment where a plurality of fuel cells, anammonia tank, and one or more adsorbents are mounted on a first stage,and one or more ammonia reactors are mounted on a second stage above thefirst stage. The aforementioned components and their assembly may beengineered so that the weight and the volume of the whole system is atmost about 25 kilograms (kg). In some cases, the total weight of thesystem, including the weight of ammonia on a full tank, may be betweenabout 24 kg and about 25 kg. In some cases, the total weight of thesystem may be between about 20 kg and about 30 kg. In some cases, thetotal weight of the system may be between about 10 kg and about 40 kg.In some cases, the total weight of the system may be at most about 25kg. In some cases, the total weight of the system may be at most about100 kg. In some cases, the total volume of the system may be betweenabout 35 L and about 37 L. The total volume may be construed as thevolume of fluid that is displaced when an object is fully immersed inthe fluid. The total volume may be construed as the sum of the volume ofindividual components and/or hardware of the system. In some cases, thetotal volume of the system may be between about 30 L and about 40 L. Insome cases, the total volume of the system may be between about 20 L andabout 50 L. In some cases, the total volume of the system may at mostabout 40 L. In some cases, the total volume of the system may be at mostabout 200 L. In some cases, the total volume of the system may bebetween about 200 L and about 1000 L.

In some cases, the components may be arranged to allow easy access tothe ammonia tank so that a user may easily exchange a tank with a fullor a partially filled tank or fill the tank with ammonia on demand. Thecomponents may also be arranged symmetrically, so that the weightdistribution of the system is balanced when mounted on the aerialdevice. FIG. 51 shows a digital rendition of an ammonia powerpack systemmounted on an aerial vehicle, in accordance with one or more embodimentsof the present disclosure.

FIG. 52 shows a photograph of an aerial vehicle with the ammoniapowerpack system mounted thereon. Flight tests were conducted with theaerial system to measure the flight duration and the power output of theammonia powerpack system. FIG. 53 shows a photograph of the aerialvehicle during flight. The specifications of the vehicle are shown belowin Table 2.

TABLE 2 Specifications of the ammonia powerpack for the ammoniapowerpack system Maximum Power 5 kW (at 100% Hydrogen Utilization byFuel Cells) Weight 25 kg Volume 36 L Fuel Capacity 16 liters tank volume/ 8.6 kg of Ammonia at full loading System Energy Density 655 Wh/kg and447 Wh/L (electrical) Conversion Efficiency (Ammonia Lower Heating Valueto Electricity) > 35% Percent Contribution of 70% on average (peakcontribution > 85%) Ammonia Powerpack to Total Power

FIG. 54 shows a test result of the aerial system through 800 seconds offlight. The total power requirement of the system was kept substantiallysteady over time, at about 3600 Watts. The power output of the batteryand the ammonia powerpack system were modulated so that the contributionof the battery decreased overtime while the total power output wasmaintained substantially the same.

In some cases, the ammonia processing and the ammonia powerpack systemmay be sized to satisfy 100% of the power requirements of a load (e.g.,the aerial vehicle). In some cases, the ammonia processing and theammonia powerpack system may be sized to satisfy 100% of the powerrequirements of a load (e.g., the aerial vehicle), and generateadditional energy to be able to charge an on-board auxiliary battery.

In some cases, the ammonia processing and the ammonia powerpack systemmay have an energy density of at least about 650 watt hours per kilogram(Wh/kg). In some cases, the ammonia processing and the ammonia powerpacksystem may have an energy density of at least about 100, 200, 300, 400,500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, or 6000 watthours per kilogram. In some cases, the ammonia processing and theammonia powerpack system may have an energy density of at most about100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000,5000, or 6000 watt hours per kilogram.

In some cases, the ammonia processing and the ammonia powerpack systemmay have an energy density of at least about 400 watt hours per liter(Wh/L). In some cases, the ammonia processing and the ammonia powerpacksystem may have an energy density of at least about 100, 200, 300, 400,500, 600, 700, 800, 900, 1000, 2000, 3000, or 4000 watt hours per liter.In some cases, the ammonia processing and the ammonia powerpack systemmay have an energy density of at most about 100, 200, 300, 400, 500,600, 700, 800, 900, 1000, 2000, 3000, or 4000 watt hours per liter.

FIGS. 81A-81B show voltage versus current and power versus current,respectively, for an integrated powerpack with a fuel cell. The fuelcell generated over 20 kilowatts of electricity using product gas from asystem comprising three electrical reactors and three combustorreactors. In some embodiments, a system may comprise one or more pairsof electrical reactor - combustion reactor modules. In some embodiments,a pair of electrical reactor - combustion reactor modules may comprisean electrical reactor and a combustion reactor connected in series flow.In some embodiments, at least two pairs of electrical reactor -combustion reactor modules may be connected in parallel flow. Purehydrogen and synthetic hydrogen/nitrogen mixture experimental resultsperformed at steady state are also shown for comparison. Slight voltagedrop for the integrated reformed ammonia fuel cell runs compared to thepure H₂ and synthetic mixture runs may occur due to fuel cell coldstart. Three different runs were performed using reformed ammoniaproduct gas. Fuel cell exit flows were supplied to the combustionheaters. The system maintained auto-thermal reforming.

In some cases, the energy density of the system may be defined as aratio between the amount of energy available in ammonia, wherein theammonia is stored within the system. In some cases, the energy densityof the system may be defined as a ratio between the amount of energyavailable in ammonia that is convertible to usable electricity, whereinthe ammonia is stored within the system. In some cases, the energydensity of the system may be defined as a ratio between the amount ofenergy available in ammonia that is convertible to usable hydrogenenergy, wherein the ammonia is stored within the system. In some cases,the system may refer to one or more ammonia tanks and one or morereactors. In some cases, the system may refer to one or more ammoniatanks, one or more reactors, and one or more fuel cells. In some cases,the system may refer to one or more ammonia tanks, one or more reactors,one or more fuel cells, and various other components coupled thereto(e.g., combustors, adsorbents, heat exchanger, electrical components, orany other components disclosed herein).

Each of the one or more reactors may be configured to crack variousamounts of ammonia per unit time. The amount of ammonia that is crackedmay be based at least partially on the size of the aerial vehicle, theweight of the aerial vehicle, whether the aerial vehicle is moving orstationary, or any combination thereof. In some cases, each of the oneor more reactors may be configured to crack at least about 30 liters ofammonia per minute (e.g., at about standard temperature and pressure).In some cases, each of the one or more reactors may be configured tocrack about 30 to 100 liters of ammonia per minute (e.g., at aboutstandard temperature and pressure). In some cases, each of the one ormore reactors may be configured to crack about 100 to 300 liters ofammonia per minute (e.g., at about standard temperature and pressure).In some cases, each of the one or more reactors may be configured tocrack at most about 1000 liters of ammonia per minute (e.g., at aboutstandard temperature and pressure). In some cases, each of the one ormore reactors may be configured to crack at most about 5000 liters ofammonia per minute (e.g., at about standard temperature and pressure).

The one or more reactors may be mounted to any side of the aerialvehicle, or to one or more sides of the aerial vehicle, e.g. a frontside, rear side, lateral side, top side, or bottom side of the aerialvehicle. As used herein, terms denoting an orientation or a direction(e.g., “front”, “rear”, “lateral”, “top”, “bottom”) may be referentialto an axis of longest dimension in a body and/or gravity or center ofgravity. For instance, in an aerial vehicle, an orientation or adirection may be referential to the longest dimension of the aerialvehicle and/or gravity. In another example, in an aerial vehiclecomprising a body that is radially symmetrical such that the aerialvehicle comprises more than one axes of longest dimension the body, anorientation or a direction may be referential to any one of the axes.

In some cases, the one or more reactors may be mounted between twoadjacent sides of the aerial vehicle. In some cases, the one or morereactors may be mounted all on one side. In some cases, the one or morereactors may be mounted on multiple sides. The one or more reactors maybe oriented to receive a flow of ammonia from a tank that is located onthe front of the aerial vehicle, behind the aerial vehicle, or from thelateral sides of the aerial vehicle. The one or more reactors may beoriented to output a flow of hydrogen, nitrogen, and/or trace ammoniatowards one or more adsorbents, heat exchangers, and/or fuel cellspositioned on the front of the aerial vehicle, behind the aerialvehicle, on a lateral side of the aerial vehicle, on the bottom of theaerial vehicle, or on the top of the aerial vehicle. The one or morereactors may be mounted onto another component that is mounted on theaerial vehicle. In some cases, the one or more reactors may comprise twoor more startup reactors and two or more main reactors. In some cases,the ammonia tank may be in fluid communication with one or more heatexchangers to vaporize the ammonia and/or to heat up the ammonia. Insome cases, the vaporized ammonia gas may be supplied to the one or morereactors.

The one or more fuel cells may be mounted to any side of the aerialvehicle, or to one or more sides of the aerial vehicle, e.g. a frontside, rear side, lateral side, top side, or bottom side of the vehicle.In some cases, the one or more fuel cells may be mounted between twoadjacent sides of the aerial vehicle. In some cases, the one or morefuel cells may be mounted all on one side. In some cases, the one ormore fuel cells may be mounted on multiple sides. In some cases, the oneor more fuel cells may be oriented to receive a flow comprising hydrogenand/or nitrogen from one or more reactors or one or more adsorbents thatare positioned on the front of the aerial vehicle, behind the aerialvehicle, on a lateral side of the aerial vehicle, on the bottom of theaerial vehicle, or on the top of the aerial vehicle. The one or morefuel cells may be oriented to output a flow comprising hydrogen and/ornitrogen towards one or more reactors or one or more combustors that arepositioned on the front of the aerial vehicle, behind the aerialvehicle, on a lateral side of the aerial vehicle, on the bottom of theaerial vehicle, or on the top of the aerial vehicle. The one or morefuel cells may be mounted onto another component that is mounted on theaerial vehicle.

The one or more motors or drive units may be mounted to any side of theaerial vehicle, or to one or more sides of the aerial vehicle, e.g. afront side, rear side, lateral side, top side, or bottom side of thevehicle. In some cases, the one or more motors or drive units may bemounted between two adjacent sides of the aerial vehicle. In some cases,the one or more motors or drive units may be mounted all on one side. Insome cases, the one or more motors or drive units may be mounted onmultiple sides. The one or more motors or drive units may be oriented toexert force on the aerial vehicle in any direction, for example, toexert force in a forward direction, in a backward direction, in asideways direction, in a vertical direction, a radial direction, or anycombination thereof. The one or more motors or drive units may beoriented to move the aerial vehicle in any direction, for example, tomove in a forward direction, in a backward direction, in a sidewaysdirection, in a vertical direction, in a radial direction, or anycombination thereof. The one or more motors or drive units may bemounted onto another component that is mounted on the aerial vehicle.

In some cases, the system may further comprise one or more adsorbents influid communication with the one or more reactors. In some cases, theone or more adsorbents may be configured to process an exit flow fromthe one or more reactors to filter out or remove ammonia from the exitflow. In some cases, the one or more adsorbents may be configured toprocess an exit flow from the one or more reactors to filter out orremove nitrogen from the exit flow. In some cases, the exit flowcomprises hydrogen and/or nitrogen. In some cases, the adsorbents may bein fluid communication with the one or more fuel cells. In some cases,the adsorbents are configured to direct the hydrogen and/or the nitrogento the one or more fuel cells after filtering out or removing theammonia from the exit flow of the one or more reactors.

The one or more adsorbents may be mounted to any side of the aerialvehicle, or to one or more sides of the aerial vehicle, e.g. a frontside, rear side, lateral side, top side, or bottom side of the vehicle.In some cases, the one or more adsorbents may be mounted between twoadjacent sides of the aerial vehicle. In some cases, the one or moreadsorbents may be mounted all on one side. In some cases, the one ormore adsorbents may be mounted on multiple sides. The one or moreadsorbents may be oriented to receive a flow comprising hydrogen,ammonia, nitrogen, or any combination thereof from one or more reactors,one or more combustors, or one or more fuel cells positioned on thefront of the aerial vehicle, behind the aerial vehicle, on a lateralside of the aerial vehicle, on the bottom of the aerial vehicle, or onthe top of the aerial vehicle. The one or more adsorbents may beoriented to output a flow comprising hydrogen and/or nitrogen bothtowards one or more fuel cells or one or more combustors positioned onthe front of the aerial vehicle, behind the aerial vehicle, on a lateralside of the aerial vehicle, on the bottom of the aerial vehicle, or onthe top of the aerial vehicle. The one or more adsorbents may be mountedonto another component that is mounted on the aerial vehicle.

In some cases, the system may further comprise one or more combustors influid communication with the one or more fuel cells. In some cases, theone or more combustors are configured to combust an exit flow from theone or more fuel cells to heat the one or more reactors. In some cases,the one or more combustors may be configured to combust a flow from theammonia tank, an exit flow from the one or more reactors, an exit flowfrom the one or more fuel cells, or any combination thereof.

In some cases, the system may further comprise a selective catalyticreduction (SCR) system configured to remove nitrous oxides (NOx) fromone or more combustion exhaust streams. In some cases, the SCR systemreceives ammonia from the one or more ammonia tanks.

The one or more combustors may be mounted to any side of the aerialvehicle, or to one or more sides of the aerial vehicle, e.g. a frontside, rear side, lateral side, top side, or bottom side of the vehicle.In some cases, the one or more combustors may be mounted between twoadjacent sides of the aerial vehicle. In some cases, the one or morecombustors may be mounted all on one side. In some cases, the one ormore combustors may be mounted on multiple sides. The one or morecombustors may be oriented to receive a flow comprising hydrogen and/ornitrogen from one or more reactors, one or more adsorbents, or one ormore fuel cells positioned on the front of the aerial vehicle, behindthe aerial vehicle, on a lateral side of the aerial vehicle, on thebottom of the aerial vehicle, or on the top of the aerial vehicle. Theone or more combustors may be oriented to output a flow comprisingcombustion byproducts to an ambient environment. The one or morecombustors may be mounted onto another component that is mounted on theaerial vehicle.

In some cases, one or more electrical heaters may be used inside the oneor more reactors. In some cases, the one or more electrical heaters maybe used in addition to the one or more combustors in the one or morereactors.

In some cases, the system may further comprise one or more fuel storagetanks mounted on the aerial vehicle. In some cases, the fuel storagetanks are in fluid communication with the one or more reactors toprovide the ammonia to the one or more reactors for cracking ordecomposition of the ammonia. In some cases, the one or more fuelstorage tank may be in fluid communication with the one or more heatexchangers to vaporize and heat up the ammonia. In some cases, thevaporized ammonia gas may be provided to the one or more reactors tocrack or decompose the ammonia.

The one or more fuel storage tanks may be mounted to any side of theaerial vehicle, or to one or more sides of the aerial vehicle, e.g. afront side, rear side, lateral side, top side, or bottom side of thevehicle. In some cases, the one or more fuel storage tanks may bemounted between two adjacent sides of the aerial vehicle. In some cases,the one or more fuel storage tanks may be mounted all on one side. Insome cases, the one or more storage tanks may be mounted on multiplesides. In some cases, the one or more fuel storage tanks may be orientedto output a flow comprising ammonia towards one or more reactorspositioned on the front of the aerial vehicle, behind the aerialvehicle, on a lateral side of the aerial vehicle, on the bottom of theaerial vehicle, or on the top of the aerial vehicle. In some cases, theone or more fuel storage tanks may be oriented to output a flowcomprising ammonia towards one or more heat exchangers positioned on thefront of the aerial vehicle, behind the aerial vehicle, on a lateralside of the aerial vehicle, on the bottom of the aerial vehicle, or onthe top of the aerial vehicle. The one or more fuel storage tanks may bemounted onto another component that is mounted on the aerial vehicle.

In some cases, the system may further comprise one or more heatexchangers for cooling an exit flow of the one or more reactors. In somecases, the one or more heat exchangers may be in thermal communicationwith an exit flow from the one or more fuel cells to cool the heatexchangers and/or the exit flow from the one or more reactors. The exitflow from the one or more fuel cells may comprise air or oxygen.

The one or more heat exchangers may be mounted to any side of the aerialvehicle, or to one or more sides of the aerial vehicle, e.g. a frontside, rear side, lateral side, top side, or bottom side of the vehicle.In some cases, the one or more heat exchangers may be mounted betweentwo adjacent sides of the aerial vehicle. In some cases, the one or moreheat exchangers may be mounted all on one side. In some cases, the oneor more heat exchangers may be mounted on multiple sides. The one ormore heat exchangers may be oriented to receive a flow comprisinghydrogen and/or nitrogen from one or more reactors, one or morecombustors, one or more fuel cells, or one or more adsorbents mounted onthe front of the aerial vehicle, behind the aerial vehicle, on a lateralside of the aerial vehicle, on the bottom of the aerial vehicle, or onthe top of the aerial vehicle. The one or more heat exchangers may beoriented to output a flow comprising hydrogen and/or nitrogen towardsone or more reactors, one or more combustors, one or more fuel cells, orone or more adsorbents mounted on the front of the aerial vehicle,behind the aerial vehicle, on a lateral side of the aerial vehicle, onthe bottom of the aerial vehicle, or on the top of the aerial vehicle.The one or more heat exchangers may be mounted onto another componentthat is mounted on the aerial vehicle.

In some cases, the one or more heat exchangers may be oriented toreceive a flow comprising ammonia from one or more ammonia storage tanksmounted on the front of the aerial vehicle, behind the aerial vehicle,on a lateral side of the aerial vehicle, on the bottom of the aerialvehicle, or on the top of the aerial vehicle. The one or more heatexchangers may be oriented to output a flow comprising ammonia towardsone or more reactors and/or one or more combustors mounted on the frontof the aerial vehicle, behind the aerial vehicle, on a lateral side ofthe aerial vehicle, on the bottom of the aerial vehicle, or on the topof the aerial vehicle. The one or more heat exchangers may be mountedonto another component that is mounted on the aerial vehicle.

In some cases, the one or more fuel cells may be in communication withan electrical load. In some cases, the electrical load may comprise theone or more motors or drive units of the aerial vehicle. In some cases,the electrical load may be one or more auxiliary electrical batteries.In some cases, the one or more fuel cells may charge one or moreelectrical batteries.

In some cases, the one or more fuel cells may be in thermalcommunication with the one or more fuel storage tanks to facilitate atransfer of thermal energy from the fuel cells to the fuel storage tanksto heat the fuel storage tanks for ammonia evaporation. In some cases,the one or more fuel cells may be in thermal communication with the oneor more air-cooled heat exchangers to facilitate a heat rejection to anambient environment. In some cases, the one or more fuel cells may be inthermal communication with the one or more heat exchangers to facilitatea transfer of thermal energy from the fuel cells to evaporate one ormore liquid or liquid/gas two phase ammonia flows.

In some cases, the system may further comprise a controller configuredto control a flow of the ammonia provided to the one or more reactorsbased on a desired power output from the one or more fuel cells. In somecases, the desired power output may be based at least partially on auser input for controlling the aerial vehicle. In some cases, thedesired power output may be based at least partially on a power outputrequired to maintain the aerial vehicle at a stationary position or tomove the aerial vehicle. In some cases, the controller may be configuredto shut off the one or more ammonia flows.

In some cases, the system may further comprise a controller operativelycoupled to one or more valves for controlling (i) a flow of the ammoniato the one or more reactors or (ii) a flow of hydrogen to the one ormore fuel cells. In some cases, the controller may be configured toprovide dynamic power control by controlling an operation of the one ormore valves. In some cases, the controller may be configured to modulatethe one or more valves connected to an ammonia storage tank to maintainor reach a threshold pressure point and increase ammonia flow rate andpower output. In some cases, the ammonia flow rate is correlated to aflow pressure of the ammonia. In some cases, the controller may beconfigured to modulate the one or more valves (e.g., solenoid valves)connected to an ammonia storage tank to maintain or reach a thresholdflow rate.

In some cases, the system may further comprise a controller and one ormore sensors operatively coupled to the controller. In some cases, thecontroller is configured to monitor a temperature of the one or morereactors, a flow pressure of the ammonia, and/or an electrical output ofthe one or more fuel cells based on one or more measurements obtainedusing the one or more sensors. In some cases, the controller may beconfigured to monitor a flow rate of the one or more ammonia flow usinga mass flow meter or a mass flow controller.

In some cases, the controller may be configured to increase an airsupply unit power to increase the air flow rate to one or morecombustors of the one or more reactors when a temperature of the one ormore reactors decreases or falls below a threshold temperature. In somecases, the threshold temperature may be about 600° C. In some cases, thethreshold temperature may be between about 550° C. to about 650° C. Insome cases, the threshold temperature may be between about 450° C. toabout 700° C. In some cases, the threshold temperature may be about 800°C. In some cases, the threshold temperature may be about 300° C. toabout 450° C.

In some cases, the system may further comprise an auxiliary electricalbattery for powering the one or more motors or drive units of the aerialvehicle. In some cases, the desired power output may be met with powercontributions from the one or more fuel cells and a second power source.In some cases, the flow of ammonia provided to the one or more reactorsmay be controlled so that the total amount of power generated by the oneor more fuel cells and the second power source meets the desired poweroutput. In some cases, the second power source may comprise an auxiliaryelectrical battery.

In some cases, the system may comprise a startup reactor. In some cases,the startup reactor may be configured to crack at least a portion of theammonia provided to the one or more reactors to yield hydrogen,nitrogen, and/or ammonia. In some cases, the startup reactor maybe influid communication with the main reactor and/or combustor. In somecases, the main reactor is configured to combust at least a portion ofan exit flow from the startup reactor to heat or pre-heat the mainreactor. In some cases, the exit flow from the startup reactor maycomprise hydrogen and at least one of ammonia or nitrogen.

In some cases, the ammonia powerpack system may follow a startupsequence. In some cases, the startup sequence may comprise a step forheating one or more reactors. In some cases, the startup sequence maycomprise a step for heating a startup reactor. In some cases, heating ofthe one or more reactors or the startup reactor may be performed usingan external power source or by combusting a fuel. In some cases, theexternal power source may be a battery (e.g., a chemical battery or anelectrical battery). In some cases, the fuel may be hydrogen, gasoline,diesel, methanol, ethanol, biodiesel, propane, butane, or any other typeof combustible material. In some cases, the external power source may beelectricity from a grid.

In some cases, the startup sequence may comprise a step for providing aflow of ammonia (NH₃) to the one or more reactors and/or the startupreactor to partially or fully crack the NH₃ flow using the one or morereactors or a startup reactor.

In some cases, the startup sequence may comprise a step for heating theone or more combustors of the main reactor by combusting an output flowfrom the startup reactor. In some cases, the output flow from thestartup reactor may comprise hydrogen and/or nitrogen. In some cases,the output flow may further comprise ammonia.

In some cases, the startup sequence may comprise a step for changing(e.g., increasing or decreasing) an NH₃ flowrate to the one or morereactors. In some cases, changing the NH₃ flowrate to the one or morereactors changes the amount of NH₃ converted to generated hydrogen. Insome cases, changing an NH₃ flowrate to the one or more reactors maycontrol the amount of hydrogen fed to the one or more fuel cells. Insome cases, changing an NH₃ flowrate to the one or more reactors maycontrol (i) the amount of hydrogen produced or the rate at whichhydrogen is produced using the one or more reactors, and/or (ii) a poweroutput from the one or more fuel cells. In some cases, a flowrate may bechanged by modulating a position of a valve between a fully open stateand a fully close state. In some cases, a flowrate may be changed usinga controller that is operatively coupled to one or more valves.

In some cases, the startup sequence may comprise a step for directing aflow comprising hydrogen and nitrogen to an adsorbent when the one ormore reactors reach a target temperature. In some cases, the startupsequence may comprise a step for directing a flow comprising hydrogenand nitrogen to an adsorbent when a target NH₃ flowrate range isreached. In some cases, the startup sequence may comprise a step fordirecting a flow comprising hydrogen and nitrogen to an adsorbent when atarget NH₃ decomposition rate is reached. In some cases, the startupsequence may comprise a step for directing a flow comprising hydrogenand nitrogen to an adsorbent, then to the one or more fuel cells, andthen to the one or more combustors, when (i) the one or more reactorsreach a target temperature, (ii) a target NH₃ flowrate range is reached,and (iii) a target NH₃ decomposition rate is reached.

In some cases, the target temperature may be between about 400° C. andabout 600° C. In some cases, the target temperature may be between about350° C. and about 650° C. In some cases, the target temperature may beat least about 350° C. In some cases, the target temperature may bebetween about 100° C. and about 600° C. In some cases, the targettemperature may be between about 600° C. and about 800° C.

In some cases, the startup sequence may comprise processing hydrogenusing the one or more fuel cells to generate electrical energy orelectrical power. In some cases, the startup sequence may comprise astep for providing electrical energy or electrical power to a load. Insome cases, the load may be one or more motors or drive units for theaerial vehicle. In some cases, the startup sequence may comprise a stepfor providing electrical energy or electrical power to one or moresensors, one or more components, and/or one or more auxiliary batteries.

Scalable Reactors for Reforming Ammonia

In some aspects, the present disclosure provides a system for processingammonia. The system may comprise one or more reactors for decomposingammonia, one or more heating elements positioned in at least one of theone or more reactors, and one or more flow channels provided around oradjacent to the one or more heating elements to enhance flow field andheating uniformity. In some cases, the one or more heating elements maybe configured to heat a fluid comprising one or more reforming gases asthe fluid flows along the one or more flow channels provided around oradjacent to the one or more heating elements. In some cases, the one ormore reforming gases may comprise ammonia. In some cases, the system mayfurther comprise one or more catalysts configured to decompose or crackammonia when heated by the one or more heating elements. In some cases,the one or more catalysts may be provided outside of or external to theone or more heating elements.

FIGS. 55A and 55B schematically illustrate an outside view and an insideview of a reactor, in accordance with one or more embodiments of thepresent disclosure. In some cases, the reactor may comprise a pluralityof gas inlets and a plurality of gas outlets. In some cases, the gasinlets may be configured to receive ammonia to be decomposed by thereactor. In some cases, the gas outlets may be configured to expelhydrogen, nitrogen, and/or unconverted ammonia. In some cases, thehydrogen and nitrogen expelled through the gas outlets may be derivedfrom the ammonia that is input into the reactor for decomposition orcracking.

In some cases, the reactor may comprise one or more embedded heatingelements. In some cases, the one or more embedded heating elements mayhave a shell or outer surface that is in thermal communication with afluid flowing through the reactor, which can enable improved heattransfer between (i) the fluid flowing through the reactor (e.g.,through one or more flow channels surrounding the embedded heatingelements) and (ii) the embedded heating elements. In some cases, the oneor more heating elements may be configured to provide a plurality ofheating zones within the reactors. In some cases, the plurality ofheating zones may have different temperatures that are predetermined oradjustable. In some cases, the embedded heating elements may comprise acombustion heater, an electrical heater, or a hybrid heating elementcomprising both a combustion heater and an electrical heater. In somecases, embedded heating elements can make reactor systems more compactby minimizing volume requirement for heating elements. In some cases, ahybrid heating element may enable faster startup and response. In somecases, a hybrid heating element may result in reactor systems that aremore compact in volume. In some cases, a hybrid heating element mayenable easier control of temperature. In some cases, a hybrid heatingelement may enable a plurality of catalyst materials to be loaded. Insome cases, a hybrid heating element may be used to control temperaturesfor a plurality of regions.

In some cases, the embedded heating elements may comprise differenttypes of heaters with different startup and response times. For example,an electrical heater may have a faster response or heating time than acombustion heater. Though a combustion heater may be used for heating,during reactor startup an electrical heater may be able to generate heatquicker than the combustion heater. In some cases, the electrical heatermay generate heat to raise the reactor temperature to an idealtemperature range quickly. In some cases, when there are suddentemperature changes, the rate of heat generation of the electricalheater may be modulated to respond to the sudden temperature changesquickly. In some cases, the combustion heater may generate heat orthermal energy quickly and respond to the sudden temperature changesquickly by supplying additional air to the combustor. In some cases, theembedded heating elements described herein may comprise both acombustion heater and an electrical heater. In some cases, one or morereactors with the one or more embedded electrical heaters may beconnected in series or parallel with one or more reactors with the oneor more embedded combustion heaters. In any of the embodiments describedherein, a combustion heater and an electrical heater may be arrangedspatially in series or spatially in parallel along a longitudinal axisof a respective reactor.

FIG. 60 schematically illustrates a gas flow path in a flow channel of areformer, in accordance with one or more embodiments of the presentdisclosure. In some cases, ammonia may be directed to flow along the gasflow path within the flow channel. In some cases, the catalysts may bepositioned in the flow channel and/or along the gas flow path for theammonia such that the ammonia comes into contact with the catalysts whenthe ammonia flows along the gas flow path within the flow channel.

FIGS. 56, 58A, and 58B schematically illustrate a top view and an insidecross-sectional view of a reformer, in accordance with one or moreembodiments of the present disclosure. In some cases, catalysts may haveammonia decomposition efficiencies that are dependent on temperature. Insome cases, precise control of temperature (both spatially andtemporally) may enhance the performance of reactors by providing idealtemperature range(s) for heating catalysts and one or more gases flowingthrough the reformer as uniformly and as quickly as possible. In somecases, the embedded heating elements described herein may be used toheat the one or more catalysts to one or more ideal temperaturerange(s). In some cases, the catalysts may be provided outside of theheating elements. In some cases, the catalysts positioned outside of theheating elements may be in thermal communication with the heatingelements to enable a transfer of thermal energy between the heatingelements and the catalysts. In some cases, extended surfaces may beprovided outside of the heating elements to enhance thermalcommunications between the catalysts and heating elements. In somecases, the one or more gases and/or the catalysts may have relativelylow thermal conductivity. In some cases, extended surfaces (e.g., finsand/or baffles) may be provided within flow channels to increase heattransfer. In some cases, the extended surface (e.g., fins and/orbaffles) may be provided within outer shell channels to increase heattransfer.

In some cases, the one or more reactors may comprise (i) a first flowpath for passage of reforming gases from one or more gas inlets along aportion of the one or more heating elements and (ii) a second flow pathfor directing reformate gases to one or more gas outlets. In some cases,the reforming gases may comprise ammonia. In some cases, reformate gasesmay comprise hydrogen and/or nitrogen. In some cases, the first flowpath may connect directly to the second flow path to enable a flow offluids between the first and second flow paths. FIGS. 56, 58A, and 58Bschematically illustrates a first flow path (solid arrows, 5601) and asecond flow path (dotted arrows, 5602) within reactors having variousdifferent cross-sectional shapes or profiles. In some cases, the firstflow path may extend from the gas inlets of the reactor along a lengthof the heating element until a gas turn around point in the reactor,after which the gases flowing along the first flow path may enter thesecond flow path via the gas turn around point. In some cases, thesecond flow path may extend back along the length of the heating elementtowards the gas outlets of the reactor.

In some cases, the first flow path and the second flow path may beoriented in different directions. In some cases, the first flow path andthe second flow path may be oriented in opposite directions. In somecases, a portion of the first flow path and a portion the second flowpath may be oriented in opposite directions.

In some cases, a reforming gas entering a reactor may have a lowertemperature than a reformate gas exiting a reactor. In some cases, thegas entering the reactor may flow along the first flow path and the gasexiting the reactor may flow along the second flow path. As describedabove, the first flow path and the second flow path may place the gasentering the reactor in thermal communication with the gas exiting thereactor. In some cases, the first flow path or the second flow path, orboth flow paths may have heat transfer enhancement mechanisms, such asmetallic fins or extended surfaces within the flow channel. By enablinga transfer of thermal energy between the gas entering the reactor andthe gas exiting the reactor, the gas entering the reactor may be heatedor pre-heated by the gas exiting the reactor, which can facilitateheating and decomposition of the gas entering the reactor. In somecases, one or more heat exchangers or heat recuperating units outside ofthe one or more reactors may be used to exchange heat between thereactor exit flows and cold incoming flows before entering the reactor.

In some cases, the first flow path and the second flow path may bepositioned adjacent to each other to enable a transfer of thermal energybetween (i) the one or more reforming gases entering the one or morereactors via the one or more gas inlets and (ii) one or more reformategases exiting the one or more reactors via the gas outlets. In somecases, each individual heating element of the one or more heatingelements may comprise one or more dedicated flow channels. In somecases, the one or more heating elements may each comprise differentrespective flow channels. In some cases, flow channels may comprise oneor more internal heat transfer enhancement mechanisms, such as fins orextended surfaces. In some cases, an outer shell (after gas turn around)in a reactor may serve as a heat exchanging channel between incomingcold gas and outgoing hot reformed gas. In some cases, an outer shellmay comprise one or more internal heat transfer enhancement mechanisms,such as fins or extended surfaces.

In some cases, the one or more reactors may comprise one or moreenclosed or partially enclosed regions which (i) comprise the one ormore flow channels and (ii) surround the one or more heating elements.In some embodiments, the one or more enclosed or partially enclosedregions may allow a passage of the one or more reforming gases aroundthe one or more heating elements to facilitate heat transfer and flowfield uniformity between the one or more heating elements and the one ormore reforming gases.

In some cases, the one or more heating elements may comprise one or moreexternal surfaces in thermal communication with the fluid flowing alongor through the one or more flow channels. In some cases, the one or morecatalysts are provided adjacent to and/or in thermal communication withthe external surfaces of the one or more heating elements. In somecases, the one or more catalysts may be located or provided within theone or more flow channels. In some cases, the one or more flow channelsmay comprise a circular cross-section to enable uniform heating of thefluid. In some cases, a volume of the reactor that is external to theembedded heating elements may be filled with the one or morecatalyst(s). In some cases, the volume of the reactor that is externalto the embedded heating elements may comprise the one or more flowchannels.

As described elsewhere herein, in some cases the reactor may comprise acircular cross-section. The circular cross-section may enable uniformheating of the catalysts since the catalysts are provided at aconsistent or similar radial distance from the embedded heating units.The circular cross-section may also enable a more uniform temperatureand/or flow distribution within the reactor. In some cases, improvedspatial uniformity of the temperature and/or flow distribution withinthe reactor may enable more uniform heating of the catalysts within thereactor such that the catalysts are collectively heated to an idealtemperature range.

In some cases, the cross-sectional size and/or shape of the flow channelaround the heating element may be adjusted or optimized to enhance flowuniformity. In some cases, a flow rate through a flow channel may bevaried depending on a predetermined heating power input to thedesignated heating element. In some cases, multiple gas outlets mayimprove flow uniformity. For example, FIGS. 62A-62D show reactorscomprising two or four gas outlets in accordance with one or moreembodiments of the present disclosure. In some cases, the four gasoutlets are positioned symmetrically such that gas flow out of thereactor is directed to each of the four sides of the reactor. In somecases, multiple gas outlets may be positioned symmetrically. In somecases, multiple gas outlets may have substantially equal cross-sectionalareas. In some cases, multiple gas outlets may be positioned on one endof a reactor. In some cases, multiple gas outlets may be positioned onmultiple sides of a reactor. In some cases, the flow channels maycomprise one or more baffles to induce turbulence, mixing, increase flowresidence time, and/or enhance flow uniformity and heat transfer. Insome cases, increasing the length of a flow path (e.g., by usingbaffles) may increase flow residence time and lead to better flowuniformity and heat transfer between (i) the embedded heating elementsand (ii) the gases flowing through the reactor or reformer.

FIG. 63A shows a plot of thermal reforming efficiencies for thepresently disclosed reactor designs as a function of ammonia flow rate.Measurements were taken using electrical joule heating only. Inletammonia gas flow was at around 25° C. Incorporating one or more heatexchangers between hot outlet flow (around 400-500° C.) and cold inletflow (around 25° C.) may significantly increase the thermal reformingefficiency (e.g., 92-95% or greater). Up to about 300 standard litersper minute (LPM) of ammonia flow were tested, where 99% conversion ofthis flow is hydrogen equivalent to about 40 kW electrical power outputfrom fuel cells. Thus, scaling the reactor design to support 100+ kWoperations may be possible, for example, with a reactor having a longerlength, or larger channel dimensions and heating elements, or morechannels and heating elements, or by stacking modular reactors. Thereactors may be constructed with great flexibility in the form factor,which may enable the use of multiple modular reactors in a system.

Some designs lacking flow channels were also tested. In some designslacking flow channels, the efficiency and conversion was outside of themeasurement range (i.e., below 80% ammonia conversion). In some designslacking flow channels, several heating elements were found to beover-heated due to insufficient heat transfer.

In some cases, the reactors disclosed herein may have a thermalreforming efficiency of at least about 90%. In some cases, the reactorsdisclosed herein may have a thermal reforming efficiency of at leastabout 50, 60, 70, 80, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99%. Insome cases, the reactors disclosed herein may have a thermal reformingefficiency of at most about 50, 60, 70, 80, 90, 91, 92, 93, 94, 95, 96,97, 98, 99%, or 100%.

FIG. 63B shows a plot of ammonia conversion efficiency for the presentlydisclosed reactor designs as a function of ammonia flow rate. In somecases, the reactors may have an ammonia conversion efficiency of atleast about 95%. In some cases, the reactors may have an ammoniaconversion efficiency of at least about 50, 60, 70, 80, 90, 91, 92, 93,94, 95, 96, 97, 98, or 99%. In some cases, the reactors may have anammonia conversion efficiency of at most about 50, 60, 70, 80, 90, 91,92, 93, 94, 95, 96, 97, 98, 99%, or 100%.

The reactors of the present disclosure may be sized appropriately togenerate various levels of power. In some cases, the reactors may beconfigured to output at least about 25 kilowatts of power. In somecases, a reactor is configured to output at least about 1, 2, 3, 4, 5,6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 200, 300, 400, or 500kilowatts of power. In some cases, the reactors may be configured tooutput at most about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60,70, 80, 90, 200, 300, 400, or 500 kilowatts of power. In some cases, thereactors may be configured to output at most about 0.1, 1, 2, 3, 4, 5,6, 7, 8, 9, 10, 20, 30, 40, 50 megawatts of power.

In some cases, the system may further comprise a plurality of differentcatalysts for decomposing ammonia. In some cases, the plurality ofdifferent catalysts may be in thermal communication with at least one ofthe one or more heating elements. FIGS. 59A and 59B schematicallyillustrate an outside view and an inside view of a reactor having twocatalysts, in accordance with one or more embodiments of the presentdisclosure. In some cases, the two catalysts may be provided in twodifferent regions or heating zones (e.g., a low-temperature region and ahigh-temperature region). In some cases, a first catalyst that isefficient at lower temperatures may be provided in a first region, and asecond catalyst that is efficient at higher temperatures may be providedin a second region. In some cases, the first region may be closer to thegas inlets and/or gas outlets of the reactor than the second region. Insome cases, one or more reactors with one or more heating elements maybe in fluid communication with one or more reactors with more or moreheating elements. For example, multiple modular reactors in series orparallel fluid communication may increase overall hydrogen generationoutput. In some cases, one or more reactors with one or more electricalheating elements may have fluid communications with one or more reactorswith more or more combustion heating elements. In some cases, one ormore reactors with one or more electrical heating elements may operateat lower temperatures than one or more reactors with one or morecombustion heating elements. In this case, exit flows of theelectrically heated reactor may enter the combustion heated reactor asinlet flows to further increase ammonia conversion and/or thermalreforming efficiency. In some cases, one or more reactors with one ormore combustion heating elements may operate at lower temperatures thanone or more reactors with one or more electrical heating elements. Insome cases, exit flows of a combustion heated reactor may enter anelectrically heated reactor as inlet flows to further increase ammoniaconversion and/or thermal reforming efficiency.

In some cases, the plurality of different catalysts may comprise a firstcatalyst with a first set of ammonia reforming properties and a secondcatalyst with a second set of ammonia reforming properties. In somecases, the ammonia reforming properties may comprise, for example,thermal reforming efficiency as a function of temperature or thermalreforming efficiency as a function of ammonia conversion. In some cases,the first catalyst and the second catalyst may be in thermalcommunication with different heating elements, different locations orregions of a same heating element, or different heating zones generatedby the one or more heating elements. In some cases, the one or moreheating elements may be configured to provide a plurality of heatingzones within the reactors. In some cases, the plurality of heating zonesmay have different temperatures that are predetermined or adjustable.

In some cases, the first catalyst and the second catalyst may havedifferent ideal temperature ranges for decomposing ammonia. In somecases, the first catalyst and the second catalyst may be provided indifferent regions or heating zones within a reactor, such that the firstcatalyst and the second catalyst are heated to their corresponding idealtemperature ranges. In some cases, the first catalyst may be heated to alower temperature range than the second catalyst. In some cases, thefirst catalyst may be heated to a higher temperature range than thesecond catalyst. In some cases, the first catalyst and the secondcatalyst may be in thermal communication with different heatingelements, different locations or regions of a same heating element, ordifferent heating zones generated by the one or more heating elements.In some cases, the first catalyst and the second catalyst may beseparated into different reactors that are in fluid communication witheach other.

In some cases, the one or more heating elements may be configured to (i)control temperatures of different regions of the one or more heatingelements or the one or more reactors or (ii) adjust a location of one ormore heating zones within the one or more reactors to optimize ammoniathermal reforming efficiency and/or conversion efficiencies.

In some cases, the system may further comprise a controller configuredto control a flow of ammonia into the one or more flow channels bymodulating one or more flow control units. In some cases, the controllermay be configured to control the flow of ammonia based on a heatingpower input to each of the one or more heating elements. In some cases,the system may further comprise a controller configured to control anoperation or a temperature of the one or more heating elements. In somecases, the controller may set or maintain a uniform temperaturedistribution within a reactor. In some cases, the uniform temperaturedistribution may correspond to spatial or temporal uniformity oftemperature or heating. In some cases, the controller may maintain auniform flow rate distribution between one or more channels within areactor.

In some cases, the system may further comprise one or more heatexchanger(s) between a hot outlet flow and a cold inlet flow of thereactors. In some cases, the controller may be configured to run astartup protocol to heat the reactor to a predetermined temperaturerange within a predetermined amount of time. In some cases, thecontroller may be operatively coupled to one or more sensors for sensing(i) a temperature of the one or more heating elements or (ii) a flowrate of ammonia or hydrogen/nitrogen mixture into the flow channels orout of the channels or (iii) one or more pressures in various locationsof the one or more reactors. In some cases, the controller may beconfigured to implement one or more control loops, for example,proportional-integral-derivative (PID), a proportional-integral (PI), ora proportional (P) control loop(s) to modulate temperatures. In somecases, controlling the operation of the heating elements may involvecontrolling a heating power input to the heating elements. In somecases, the one or more flow control units may comprise one or morevalves and/or one or more pressure sensors.

The reactors disclosed herein may comprise various shapes or sizes. Forexample, FIGS. 55A and 55B schematically illustrate an outside view andan inside view of a reactor with a circular cross section having aplurality of gas inlets and a plurality of gas outlets. In anotherexample, FIGS. 57A and 57B schematically illustrate an outside view andan inside view of a reactor with a square cross section having aplurality of gas inlets and a plurality of gas outlets. FIG. 61 showsadditional non-limiting examples of various reactor configurations. Insome cases, the reactor may comprise various other cross-sectionalshapes or profiles, including but not limited to, triangular,rectangular, pentagonal, hexagonal, heptagonal, or octagonal shapes orprofiles. In some cases, the one or more reactors may comprise across-sectional shape comprising a circle, an ellipse, an oval, or anypolygon comprising three or more sides. In some cases, the one or morereactors may comprise a cross-sectional shape that is similar to across-sectional shape of the flow channels. In some cases, the one ormore reactors may comprise a cross-sectional shape that is differentthan a cross-sectional shape of the flow channels.

In some cases, the cross-sectional shape of the reactor may permitstacking of a plurality of reactors. In some cases, a plurality ofreactors may be stacked horizontally (i.e., laying down) or vertically(i.e., standing up). In some cases, a plurality of reactors may bestacked in a rectangular or square grid pattern. In some cases, aplurality of reactors may be stacked in a hexagonal grid pattern (i.e.,honeycomb). In some cases, a plurality of reactors may be stacked andconnected linearly.

The reactors disclosed herein may comprise any numbers of gas inlets andgas outlets. In some cases, the reactor may comprise one or more gasinlets or gas outlets. In some cases, the reactor may comprise two ormore gas inlets or gas outlets. In some cases, the reactor may comprisea single gas inlet and/or a single gas outlet. In some cases, thereactor may comprise a single gas inlet and/or a single gas outletwhereas flow is distributed to one or more flow channels internally. Insome cases, the reactor may comprise at least about 1, 2, 3, 4, 5, 6, 7,8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 gas inlets or gasoutlets. In some cases, the reactor may comprise at most about 1, 2, 3,4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 gas inletsor gas outlets.

In some cases, the one or more gas inlets may be oriented parallel to alengthwise direction of a reactor. In some cases, the one or more gasinlets may be oriented perpendicular to the lengthwise direction of areactor. In some cases, the one or more gas outlets may be orientedparallel to a lengthwise direction of a reactor. In some cases, the oneor more gas outlets may be oriented perpendicular to the lengthwisedirection of a reactor. The gas inlets and/or the gas outlets may beoriented in any direction relative to the reactor.

The reactor may comprise various length to width ratios. FIGS. 62A - 62Dshow examples of reactor designs having different length to widthratios, in accordance with one or more embodiments of the presentdisclosure. FIG. 62A shows a first design having a square form factor.FIG. 62B shows a second design having a square form factor, but 50%longer in length than the first design. FIG. 62C shows a third designhaving a square form factor, but 50% larger in flow channel and heaterdiameters than the first design. FIG. 62D shows a fourth design having acylindrical form factor, having the same flow channel and heaterdiameters as the second design. In some cases, the length of the reactormay be at least about 5 times longer than the width or diameter of thereactor. In some cases, the length of the reactor may be at least about2, 3, 4, 5, 6, 7, 8, 9, or 10 times longer than the width or diameter ofthe reactor. In some cases, the length of the reactor may be at mostabout 2, 3, 4, 5, 6, 7, 8, 9, or 10 times longer than the width ordiameter of the reactor. In some cases, the length of the reactor may beat most about 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 times longer thanthe width or diameter of the reactor.

In any of the embodiments described herein, the system or powerpack unitmay comprise a pressure swing adsorption (PSA) or a membrane separationunit. The PSA or membrane separation unit may be configured to removenitrogen from an exit flow of the one or more reactors. The PSA ormembrane separation unit may be located or positioned downstream of oneor more adsorbents in fluid communication with the one or more reactors.The PSA or membrane separation unit may be located or positionedupstream of one or more fuel cells. In some cases, the PSA or membraneseparation unit may be further configured to remove trace ammonia froman exit flow from the one or more adsorbents or the one or morereactors. In some cases, the PSA or membrane separation unit may beconfigured to process an exit flow from the one or more adsorbents orthe one or more reactors to produce a discharge stream comprisingnitrogen and hydrogen. In some cases, the discharge stream may besupplied to a combustion heater of the one or more reactors.

In some embodiments, the system or powerpack unit may comprise one ormore combustors. In some cases, the one or more combustors may consumeabout 15 to 50 percent of the total hydrogen produced from ammoniareforming as a combustion fuel. In some cases, the one or morecombustors may consume about 30 to 40 percent of the total hydrogenproduced from ammonia reforming as a combustion fuel. In some cases, theone or more combustors may consume about 25 to 45 percent of the totalhydrogen produced from ammonia reforming as a combustion fuel. In somecases, the one or more combustors may consume less than about 30 percentof the total hydrogen produced from ammonia reforming as a combustionfuel. In some cases, the one or more combustors may consume less thanabout 25 percent of the total hydrogen produced from ammonia reformingas a combustion fuel. In some cases, the one or more combustors mayconsume less than about 80, 70, 60, 50, 40, 30, 20, or 10 percent of thetotal hydrogen produced from ammonia reforming as a combustion fuel. Insome cases, the one or more combustors may consume more than about 80,70, 60, 50, 40, 30, 20, or 0 percent of the total hydrogen produced fromammonia reforming as a combustion fuel.

In one or more of the embodiments described herein, one or moreelectrical heaters at least partially embedded in one or more reactorsmay provide heating only during a startup operation. In some cases, theone or more electrical heaters turns on and off intermittently duringoperation, either by automatically turning the electrical heater on andoff (e.g., based on a temperature measured in a reactor and/or heater)or by manually turning the electrical heater on and off (e.g., based ona user input to an input device, such as a button, switch, knob, mouse,keyboard, etc.). In some cases, the one or more electrical heatersprovide about 30% to 50% of the total heating power requirement duringoperation. In some cases, the one or more electrical heaters provideabout 15% to 40% of the total heating power requirement duringoperation. In some cases, the one or more electrical heaters provideless than 15% of the total heating power requirement during operation.In some cases, the one or more electrical heaters provide about 50% to70% of the total heating power requirement during operation. In somecases, the one or more electrical heaters provide at least 70% of thetotal heating power requirement intermittently. In some cases, the oneor more electrical heaters provide about 100% of the total heating powerrequirement intermittently. In some cases, the total heating powerrequirement is based on sum of Joule heating and combustion energy inputto maintain auto-thermal reforming.

In any of the embodiments described herein, the system or powerpack unitmay output an ammonia lower heating value to useful electricityconversion efficiency of about 20 to 60%. In some cases, the system orpowerpack unit may output an ammonia lower heating value to usefulelectricity conversion efficiency of about 30 to 50%. In some cases, thesystem or powerpack unit may output an ammonia lower heating value touseful electricity conversion efficiency of about 35 to 45%. In somecases, the system or powerpack unit may output an ammonia lower heatingvalue to useful electricity conversion efficiency of greater than about35%.

In any of the embodiments described herein, one or more combustionheaters at least partially embedded in one or more reactors may havepressure drops of combustion fuel and air flows across the one or morecombustion heaters of less than 5 bar. In some cases, one or morecombustion heaters may have pressure drops of combustion fuel and airflows across the one or more combustion heaters of less than 2 bar. Insome cases, one or more combustion heaters may have pressure drops ofcombustion fuel and air flows across the one or more combustion heatersof less than 1 bar. In some cases, one or more combustion heaters mayhave pressure drops of combustion fuel and air flows across the one ormore combustion heaters of less than 0.5 bar.

In any of the embodiments described herein, the system or powerpack unitmay be utilized for stationary applications and/or mobile applications.Stationary applications may involve the generation of electricity orhydrogen for non-mobility applications or platforms (e.g., to supplypower and/or hydrogen to a network or a grid). Mobile applicationsinvolve the generation of electricity and/or hydrogen for mobileapplications or platforms (e.g., vehicles or other movable platforms).

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. It is not intendedthat the invention be limited by the specific examples provided withinthe specification. While the invention has been described with referenceto the aforementioned specification, the descriptions and illustrationsof the embodiments herein are not meant to be construed in a limitingsense. Numerous variations, changes, and substitutions will now occur tothose skilled in the art without departing from the invention.Furthermore, it shall be understood that all aspects of the inventionare not limited to the specific depictions, configurations or relativeproportions set forth herein which depend upon a variety of conditionsand variables. It should be understood that various alternatives to theembodiments of the invention described herein may be employed inpracticing the invention. It is therefore contemplated that theinvention shall also cover any such alternatives, modifications,variations or equivalents. It is intended that the following claimsdefine the scope of the invention and that methods and structures withinthe scope of these claims and their equivalents be covered thereby.

What is claimed is:
 1. A system for ammonia (NH₃) decomposition,comprising: an ammonia reforming reactor, comprising: a housingcomprising a plurality of inner flow paths and an outer flow path,wherein the plurality of inner flow paths is in fluid communication withthe outer flow path, and one or more NH₃ reforming catalysts capable ofreforming NH₃ to generate a reformate stream, wherein the reformatestream comprises hydrogen and nitrogen, wherein the one or more NH₃reforming catalysts are located in at least one of (i) the plurality ofinner flow paths or (ii) the outer flow path; and a plurality ofheaters, wherein each inner flow path is configured to be heated by atleast one of the plurality of heaters, wherein each inner flow path isin thermal communication with the at least one of the plurality ofheaters along a length of the inner flow path.
 2. The system of claim 1,wherein the one or more NH₃ reforming catalysts comprise: a first NH₃reforming catalyst that is configured to contact ammonia at a firsttemperature range to generate reformate; and a second NH₃ reformingcatalyst that is configured to contact the ammonia at a secondtemperature range to generate additional reformate, wherein the secondtemperature range is greater than the first temperature range, whereinan ammonia conversion efficiency of the first NH₃ reforming catalyst ishigher at the first temperature range compared to an ammonia conversionefficiency of the second NH₃ reforming catalyst at the first temperaturerange.
 3. The system of claim 2, wherein the first NH₃ reformingcatalyst and the second NH₃ reforming catalyst are in thermalcommunication with different heaters of the plurality of heaters.
 4. Thesystem of claim 2, wherein the first NH₃ reforming catalyst and thesecond NH₃ reforming catalyst are in thermal communication withdifferent heating regions of a same heater of the plurality of heaters.5. The system of claim 2, wherein the first NH₃ reforming catalystcomprises ruthenium (Ru), platinum (Pt), or palladium (Pd).
 6. Thesystem of claim 2, wherein the second NH₃ reforming catalyst comprisesnickel (Ni), cobalt (Co), molybdenum (Mo), iron (Fe), or copper (Cu). 7.The system of claim 1, wherein each inner flow path is configured to beheated by at least two of the plurality of heaters.
 8. The system ofclaim 1, wherein the plurality of heaters comprises at least oneelectrical heater.
 9. The system of claim 1, wherein the plurality ofheaters comprises at least one combustion heater.
 10. The system ofclaim 1, wherein the housing comprises a circular cross-sectional shapeor a rectangular cross-sectional shape.
 11. The system of claim 1,further comprising a plurality of inlets for directing the NH₃ to theammonia reforming reactor, wherein one or more respective inlets of theplurality of inlets is in fluid communication with a correspondingrespective inner flow path of the plurality of inner flow paths.
 12. Thesystem of claim 1, further comprising at least one outlet configured todirect the reformate stream out of the ammonia reforming reactor,wherein the at least one outlet is in fluid communication with the atleast one outer flow path.
 13. The system of claim 1, wherein at leastone of the plurality of heaters is configured to control temperatures ofdifferent regions of the ammonia reforming reactor based on an ammoniaconversion efficiency measured downstream of the ammonia reformingreactor.
 14. The system of claim 1, wherein at least one of theplurality of heaters is configured to adjust a location of a heatingregion in the ammonia reforming reactor based on an ammonia conversionefficiency measured downstream of the ammonia reforming reactor.
 15. Thesystem of claim 1, further comprising a baffle or fin configured toenhance heat transfer in or adjacent to at least one of the plurality ofinner flow paths or the at least one outer flow path.
 16. The system ofclaim 1, wherein the system further comprises an ammonia storage tankand a fuel cell, wherein the system comprises a volumetric energydensity of greater than about 400 Watt-hours (Wh) of electricity perliter and less than about 3000 Wh of electricity per liter.
 17. A methodfor ammonia (NH₃) decomposition, comprising: contacting, in an ammoniareforming reactor, ammonia with one or more NH₃ reforming catalystscapable of reforming NH₃ to generate a reformate stream, wherein thereformate stream comprises hydrogen and nitrogen, wherein the ammoniareforming reactor comprises: (a) a housing comprising a plurality ofinner flow paths and an outer flow path, wherein the plurality of innerflow paths is in fluid communication with the outer flow path; and (b) aplurality of heaters, wherein each inner flow path is configured to beheated by at least one of the plurality of heaters, wherein each innerflow path is in thermal communication with the at least one of theplurality of heaters along a length of the inner flow path, and whereinthe one or more NH₃ reforming catalysts are located in at least one of(i) the plurality of inner flow paths and (ii) the outer flow path. 18.The method of claim 17, wherein the one or more NH₃ reforming catalystscomprise a first NH₃ reforming catalyst and a second NH₃ reformingcatalyst, wherein: (1) the ammonia is contacted with the first NH₃reforming catalyst at a first temperature range to generate reformate;and (2) the ammonia is contacted with the second NH₃ reforming catalystat a second temperature range to generate additional reformate, whereinthe second temperature range is greater than the first temperaturerange, wherein an ammonia conversion efficiency of the first NH₃reforming catalyst is higher at the first temperature range compared toan ammonia conversion efficiency of the second NH₃ reforming catalyst atthe first temperature range.
 19. The method of claim 18, wherein thefirst NH₃ reforming catalyst and the second NH₃ reforming catalyst arein thermal communication with different heaters of the plurality ofheaters.
 20. The method of claim 18, wherein the first NH₃ reformingcatalyst and the second NH₃ reforming catalyst are in thermalcommunication with different heating regions of a same heater of theplurality of heaters.
 21. The method of claim 18, wherein the first NH₃reforming catalyst comprises ruthenium (Ru), platinum (Pt), or palladium(Pd).
 22. The method of claim 18, wherein the second NH₃ reformingcatalyst comprises nickel (Ni), cobalt (Co), molybdenum (Mo), iron (Fe),or copper (Cu).
 23. The method of claim 17, wherein the plurality ofheaters comprises at least one electrical heater.
 24. The method ofclaim 17, wherein the plurality of heaters comprises at least onecombustion heater.
 25. The method of claim 17, wherein the housingcomprises a circular cross-sectional shape or a rectangularcross-sectional shape.
 26. The method of claim 17, further comprisingdirecting the NH₃ to the ammonia reforming reactor using a plurality ofinlets, wherein one or more respective inlets of the plurality of inletsis in fluid communication with a corresponding respective inner flowpath of the plurality of inner flow paths.
 27. The method of claim 17,further comprising directing the reformate stream out of the ammoniareforming reactor using at least one outlet, wherein the at least oneoutlet is in fluid communication with the at least one outer flow path.28. The method of claim 17, further comprising using at least one of theplurality of heaters, controlling temperatures of different heatingregions of the ammonia reforming reactor based on an ammonia conversionefficiency measured downstream of the ammonia reforming reactor.
 29. Themethod of claim 17, further comprising using at least one of theplurality of heaters, adjusting a location of a heating region in theammonia reforming reactor based on an ammonia conversion efficiencymeasured downstream of the ammonia reforming reactor.
 30. The method ofclaim 17, further comprising using a baffle or fin to enhance heattransfer in or adjacent to at least one of the plurality of inner flowpaths or the at least one outer flow path.